Annals of Botany 106: 107 –130, 2010
doi:10.1093/aob/mcq090, available online at www.aob.oxfordjournals.org
Phylogenetic studies favour the unification of Pennisetum, Cenchrus and
Odontelytrum (Poaceae): a combined nuclear, plastid and morphological
analysis, and nomenclatural combinations in Cenchrus
M. Amelia Chemisquy 1,*, Liliana M. Giussani 1, Marı́a A. Scataglini 1, Elizabeth A. Kellogg 2
and Osvaldo Morrone 1
1
Instituto de Botánica Darwinion, Labardén 200, Casilla de Correo 22, B1642HYD, San Isidro, Buenos Aires, Argentina and
2
University of Missouri-St. Louis, One University Boulevard, St Louis, MO 63121, USA
* For correspondence. E-mail machemisquy@darwin.edu.ar
Received: 22 April 2009 Returned for revision: 17 December 2009 Accepted: 29 March 2010
† Backgrounds and Aims Twenty-five genera having sterile inflorescence branches were recognized as the bristle
clade within the x ¼ 9 Paniceae (Panicoideae). Within the bristle clade, taxonomic circumscription of Cenchrus
(20–25 species), Pennisetum (80 –140) and the monotypic Odontelytrum is still unclear. Several criteria have
been applied to characterize Cenchrus and Pennisetum, but none of these has proved satisfactory as the diagnostic
characters, such as fusion of bristles in the inflorescences, show continuous variation.
† Methods A phylogenetic analysis based on morphological, plastid (trnL-F, ndhF) and nuclear (knotted) data is
presented for a representative species sampling of the genera. All analyses were conducted under parsimony,
using heuristic searches with TBR branch swapping. Branch support was assessed with parsimony jackknifing.
† Key Results Based on plastid and morphological data, Pennisetum, Cenchrus and Odontelytrum were supported
as a monophyletic group: the PCO clade. Only one section of Pennisetum (Brevivalvula) was supported as monophyletic. The position of P. lanatum differed among data partitions, although the combined plastid and morphology and nuclear analyses showed this species to be a member of the PCO clade. The basic chromosome
number x ¼ 9 was found to be plesiomorphic, and x ¼ 5, 7, 8, 10 and 17 were derived states. The nuclear phylogenetic analysis revealed a reticulate pattern of relationships among Pennisetum and Cenchrus, suggesting that
there are at least three different genomes. Because apomixis can be transferred among species through hybridization, its history most likely reflects crossing relationships, rather than multiple independent appearances.
† Conclusions Due to the consistency between the present results and different phylogenetic hypotheses (including morphological, developmental and multilocus approaches), and the high support found for the PCO clade,
also including the type species of the three genera, we propose unification of Pennisetum, Cenchrus and
Odontelytrum. Species of Pennisetum and Odontelytrum are here transferred into Cenchrus, which has priority.
Sixty-six new combinations are made here.
Key words: Pennisetum, Cenchrus, Odontelytrum, Poaceae, phylogenetic analyses, ndhF, trnL-trnF, kn1,
apomixis.
IN T RO DU C T IO N
Morphological and molecular phylogenetic studies of the grass
subfamily Panicoideae have shown that Pennisetum Rich. and
Cenchrus L. are closely related genera within the bristle
clade in tribe Paniceae (Gómez-Martı́nez and Culhman,
2000; Zuloaga et al., 2000; Duvall et al., 2001; Giussani
et al., 2001; Kellogg et al., 2004; Bess et al., 2005; Doust
et al., 2007; Donadı́o et al., 2009). This clade includes
approximately 25 genera (Cenchrus, Ixophorus Schltdl.,
Paspalidium Stapf, Pennisetum and Setaria P.Beauv., among
others), and is characterized by the presence of setae or bristles
in the inflorescences, derived from inflorescence branch meristems (Doust and Kellogg, 2002; Bess et al., 2005).
Pennisetum and Cenchrus are distributed throughout tropical and subtropical regions of the Old and New World and
contain 80– 140 and 20– 25 species, respectively (e.g.
DeLisle, 1963; Türpe, 1983; Clayton and Renvoize, 1986;
Crins, 1991; Watson and Dallwitz, 1992). Some species of
Pennisetum are cultivated as cereal and forage grasses (e.g.
P. purpureum Schumach. ‘elephant grass’, P. glaucum (L.)
R.Br. ‘pearl millet’, P. clandestinum Hochst. ex Chiov.
‘kikuyu grass’) or ornamentals (e.g. P. setaceum (Forssk.)
Chiov. ‘tender fountaingrass’, P. alopecuroides (L.) Spreng.
‘foxtail fountaingrass’), and some species of Cenchrus and
Pennisetum are considered important weeds (e.g. C. ciliaris
L. ‘buffel grass’, C. echinatus L. ‘southern sandbur’,
C. myosuroides Kunth ‘big sandbur’ and P. polystachion (L.)
Schult. ‘mission grass’) (DeLisle, 1963; Clayton and
Renvoize, 1986; Watson and Dallwitz, 1992; Rúgolo de
Agrasar and Puglia, 2004).
Pennisetum is not clearly distinguished from Cenchrus, and
several species that are now included in Cenchrus have previously been assigned to Pennisetum. For example, P. ciliare
is accepted by Chase (1921), Pohl (1980), Judziewicz (1990)
and Wipff (2003), whereas it is treated under Cenchrus by
DeLisle (1963), Clayton (1989), Pohl and Davidse (1994),
Zuloaga and Morrone (2003), and Chen and Phillips (2006).
# The Author 2010. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.
For Permissions, please email: journals.permissions@oxfordjournals.org
108
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
The degree of fusion of the bristles is commonly used to separate these genera (Pilger, 1940; DeLisle, 1963; Clayton, 1972,
1989; Clayton and Renvoize, 1982, 1986; Filgueiras, 1984;
Watson and Dallwitz, 1992). In most New World species of
Cenchrus the degree of fusion is substantial, although there
are several Old World species in which this distinction is
less obvious (Crins, 1991). Other characters used to distinguish
the genera are the presence of pedicellate spikelets and
whether the bristles are flattened or stiff. However, none of
these characters can be applied effectively to segregate the
genera (Webster, 1988). Correll and Johnston (1970) treated
Pennisetum under Cenchrus and presented several diagnostic
features for the combined genus.
The species now included in Pennisetum (Stapf and
Hubbard, 1934; Türpe, 1983; Wipff, 2001, 2003) have been
previously placed in the genera Cenchrus, Gymnotrix
P.Beauv., Holcus L., Panicum L., Penicillaria Willd. and
Setaria. Most members of the genus are perennial.
Distinctive characteristics of the genus include the shape and
arrangement of the inflorescences, which are paniculate, contracted and spike-like, with fascicles of spikelets on reduced
axes that disarticulate at maturity. The rachis terminates in a
bristle; the bristles that subtend the spikelets are free, often
plumose and disarticulate with the spikelets (Crins, 1991).
Wipff (2003) characterized Pennisetum as having antrorsely
scabrous bristles (not spiny) with fascicle axes that terminate
in a bristle, and basic chromosome numbers of x ¼ 5, 7, 8 or
9; he considered Cenchrus as having retrorsely scabrous,
spiny bristles, fascicle axes that are terminated in a spikelet
and a basic chromosome number of x ¼ 7.
Authors have applied different criteria to subdivide
Pennisetum. Stapf and Hubbard (1934) recognized five sections: Gymnotrix (P.Beauv.) Steud. (with two subsections,
Acrostigma (Leeke) Stapf & C.E.Hubb. and Pleurostigma
(Leeke) Stapf & C.E.Hubb.), Pennisetum, Penicillaria
(Willd.) Benth & Hook.f. nom. superf., Heterostachya
Schumach. and Brevivalvula Döll. Pilger (1940) recognized
three subgenera: Dactylophora Leeke, Eriochaeta (Fig. & De
Not.) Leeke (equivalent to section Brevivalvula) and
Pennisetum; the latter was divided into sections Cenchropsis
(Leeke) Pilg., Gymnotrix (with three subsections:
Acrostigma, Beckeropsis (Fig. & De Not.) Pilg. and
Pleurostigma) and Penicillaria. Brunken (1977) revised
section Pennisetum and concluded that Penicillaria was a
synonym of this type section. Finally, Clayton and Renvoize
(1986) recognized only sections Brevivalvula, Dactylophora
nom. inval., Gymnotrix (with the same subsections as
Pilger), Heterostachya and Pennisetum. The differences
between the sections are often weak (Schmelzer, 1997) and
are based mainly on morphological characters of the inflorescence. Scholz (2006) established a new monotypic genus,
Kikuyochloa, based on Pennisetum clandestinum. The inflorescences in Kikuyochloa are hidden in the leaf sheaths and the
spikelets are arranged in simple units without a ring of
basal, involucral bristles; the tiny bristles of the individual spikelets never completely encircle the spikelets.
Several cereals or forage species of Pennisetum are very
important resources for food (e.g. P. glaucum). A phylogenetic
approach and information relating to the ploidy of the species
could prove useful in clarifying the relatedness of species
without the necessity of crossing, in particular when species
are difficult to cultivate. Using internal transcribed spacer
(ITS) data, Martel et al. (2004) placed two wild forms of
Pennisetum glaucum (L.) R.Br. subsp. monodii (Maire)
Brunken in the primary gene pool of domesticated
P. glaucum (diploid, x ¼ 7), where the primary gene pool is
defined as taxa that are as easy to cross as within the same
species (Harlan and de Wet, 1971). In the secondary gene
pool (coenospecies where gene transfer is possible, but
fertile hybrids are difficult to obtain) they placed
P. purpureum (tetraploid, x ¼ 7). All remaining species of
Pennisetum were in the tertiary gene pool (species for which
hybrids with the crop would be difficult to obtain and maintain, representing the extreme outer limit of potential genetic
exchange; cf. Harlan and de Wet, 1971).
Several basic chromosome numbers have been reported for
Cenchrus (x ¼ 9, 10, 17) and Pennisetum (x ¼ 5, 7, 8, 9, 17;
Table 1). The genera are included in the x ¼ 9 Paniceae clade,
and the basic chromosome number x ¼ 9 is plesiomorphic
within the bristle clade and the Pennisetum – Cenchrus clade
(Giussani et al., 2001; Martel et al., 2004; Donadı́o et al.,
2009). Although diploids are not rare among species of
Cenchrus and Pennisetum, polyploid and aneuploid numbers
are common within both genera (Table 1). A high frequency
of univalents or multivalent associations in metaphase I
(e.g. Sisodia, 1970), lagging chromosomes in anaphase I
(Dujardin and Hanna, 1984a) and anomalies in meiosis
provide evidence of outbreeding in polyploid species of
Pennisetum (P. polystachion, P. pedicellatum Trin.,
P. squamulatum Fresen.) and Cenchrus (C. ciliaris, C. incertus
M.A.Curtis, C. setigerus Vahl.). In this context, consistency
and incongruence among plastid (maternal) and nuclear (biparental) phylogenetic analyses should help to elucidate the origin
of allopolyploids (e.g. P. pedicellatum, P. polystachion).
Apospory is a mode of asexual reproduction in which a
gametophyte develops directly from diploid cells of the sporophyte without meiosis (Gustafsson, 1946). This apomictic
mode is well documented in Panicoideae (Brown and Emery,
1958), being frequent in several species of Cenchrus and
Pennisetum (Ozias-Akins et al., 2003; Ozias-Akins, 2006),
and its developmental pattern has been well studied in
Cenchrus ciliaris and Pennisetum squamulatum (Dujardin
and Hanna, 1984a; Ozias-Akins et al., 1998; Wen et al.,
1998). Evidence for transmission of apomixis by a single
chromosome was reported by Ozias-Akins et al. (1993), and
subsequent studies have identified molecular markers linked
to apomixis (Ozias-Akins et al., 2003). An apospory-specific
genomic region (ASGR) (Ozias-Akins et al., 1998), located
on a single chromosome, is necessary and sufficient for the
expression of apomixis in polyploid taxa (Goel et al., 2003).
Also, at least two genes, Pca21 and Pca24, were identified
to play a role during apomictic development in Pennisetum
ciliare or Cenchrus ciliaris (Singh et al., 2007), although
they can be inherited independently of the ASGR.
Previous phylogenetic studies showed that Pennisetum and
Cenchrus form a strongly supported monophyletic group
(Martel et al., 2004; Doust et al., 2007; Donadı́o et al.,
2009). Donadı́o et al. (2009), using two plastid markers and
including almost 20 and seven species of Pennisetum and
Cenchrus, respectively, found the former to be polyphyletic.
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
109
TA B L E 1. Chromosome numbers and reproductive behaviour reported for the species included in the analyses
Species
Cenchrus agrimonioides
C. brownii
C. caliculatus
C. ciliaris
C. echinatus
C. incertus
C. myosuroides
C. pilosus
C. setigerus
Ixophorus unisetus
Odontelytrum abyssinicum
Paspalidium geminatum
Pennisetum sect. Brevivalvula †
P. hordeoides
P. pedicellatum
2n
n
Reproductive
behaviour
x
–
34(14)
34(30)
16(18), 17(43), 18(18)(22)
34(14)(18)
16(22), 17(18)(14)
27(6), 35(18)
17(14)
17(43), 18(47)
–
–
9(43)
–
34(48), 36(26)(24), 70(23)
–
34(23), 36(16)(24), 45(32), 54(26), 63(32), 78(23), 90(32)
68 (27)(45)(25)(23), 70(23)
30(22), 34(24)(14)(48)
54(6), 70(3)(23)(50)
34(14)(48)
34(47), 36(46), 37(47)
34(49)
–
18(56), 36(24)
–
9*, 17(14)(14)
17*
9(43)
17(18)(22)
17(14)(18)
9, 10(17)
17(14)(14)
9(43), 17(43)
17*
–
9(43)
–
–
–
APO, SEX(53)
–
SEX(59)
SEX(59)
–
APO(46)
–
–
–
9(51)
–
36(51), 54(51)
24(60), 30(60), 32(60), 35(60), 36(60), 42(60), 45(51), 48(60),
53(60), 54(36)(51)
18(51), 24(60), 32(60), 36(51), 45(51), 48(60), 52(60), 53(48),
54(36)(51)(13)(27), 56(60), 63(60), 78(23)
36(7)
9(1)
9(36)(51)
APO(53)
APO(36)(53)
9(36)(51)
APO(20)(53)
9*
–
P. polystachion subsp.
18(13), 36(12)
polystachion
P. polystachion subsp. atrichum
–
Pennisetum sect. Dactylophora †
P. lanatum
18(43)
Pennisetum sect. Gymnotrix subsect. Acrostigma †
P. alopecuroides
–
P. basedowii
–
P. chilense
–
P. frutescens
–
P. glaucocladum
–
P. macrourum
–
P. massaicum
–
P. mezianum
–
P. natalense
–
P. nervosum
–
P. ramosum
–
P. sphacelatum
18(32)
P. thunbergii
–
Pennisetum sect. Gymnotrix subsect. Beckeropsis †
P. montanum
16(31)
P. unisetum
–
Pennisetum sect. Gymnotrix subsect. Pleurostigma †
P. latifolium
–
P. trachyphyllum
–
P. tristachyum
–
Pennisetum sect. Heterostachya †
P. schweinfurthii
–
P. squamulatum
–
Pennisetum sect. Pennisetum †
P. clandestinum
18(38), 27(34)
P. flaccidum
9(34), 27(43)
P. foermeranum
–
P. glaucum
7(43)
P. orientale
9, 18(43)
P. purpureum
7(1), 28(34)
P. setaceum
–
P. sieberianum
–
P. villosum
–
P. violaceum
–
Pseudoraphis paradoxa
–
P. spinescens
–
Rupichloa acuminata
13(42)
Setaria palmifolia
27(41)(38)
S. sphacelata
9(28), 18(28), 27(28)
S. parviflora
18(28)(38)
Spinifex sericeus
–
(43)
–
9
–
18(36)(54)
54(20)
–
63(45)
–
36(20)
16(46), 32(55)
16(52), 32(36)
–
36(45), 72(48)
10(36)(52)(55)
–
18(16)
9(36)
9*
–
9(45)
–
9(46)
8(46)
8(36, 52)
–
9(45)
5(36)(52)(55)
9*
9*
SEX(36)
–
–
APO(53)
–
APO(20)(53)
APO, SEX(53)
APO(36)
–
–
APO, SEX(36)
–
–
–
18(16)
8(31)
9*
–
–
36(45)
–
–
9(45)
–
–
APO(53)
–
–
14(36)(52)
54(36), 56(2)
7(36)(52)
7(2), 9(20)(36)
SEX(36)
APO(20)(36)(53)
36(29)(45)(56)
18(46), 36(9)(46)
–
14(8)(36)
36(36)(29), 45(40)
27(26), 28(36)(8)(33),
27(36)(29), 54(36), 68(58)
–
18(46), 27(46), 36(36), 45(45), 54(45)
14(36)
–
32(27)
–
54(27)
36(5), 54(28)
36(25)(15)
18(57)
9(29)
9(43)
–
7(36)(43)
9(36)
7(36)(45)
9(36), 17(58)
–
9(36)
7(36)
–
8*
13(42)
9*
9*
9*
9(57)
APO, SEX(46)
APO(46), SEX(53)
–
SEX(36)
APO(36)(53), SEX(53)
APO(59), SEX(36)
APO(53)
–
APO(36)(53)
SEX(36)
–
–
–
–
SEX(59)
–
–
Continued
110
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
T A B L E 1. Continued
Species
2n
n
Stenotaphrum secundatum
–
18(45)(6)(24), 36(27)
x
9(45)
Reproductive
behaviour
SEX(59)
References: (1) Akenova and Chehheda (1981), (2) Akiyama et al. (2006), (3) Avdulov (1931), (4) Bir and Sahni (1986), (5) Bir and Sahni (1987),
(6) Brown (1950), (7) Brunken (1979), (8) Burton (1942), (9) Chatterji and Timothy (1969), (10) Chopanov and Yurtsev (1976), (11) Christopher and
Abraham (1976), (12) Davidse and Pohl (1972), (13) Davidse and Pohl (1978), (14) Davidse and Pohl (1974), (15) de Wet (1954), (16) de Wet (1960), (17)
DeLisle (1963), (18) DeLisle (1964), (19) Dujardin (1979), (20) Dujardin and Hanna (1984b), (21) Emery (1957), (22) Gould (1958), (23) Gould (1965), (24)
Gould (1968), (25) Gould and Soderstom (1967), (26) Gould and Soderstrom (1970), (27) Gould and Soderstrom (1974), (28) Gupta and Singh (1977), (29)
Hrishi (1952), (30) Hsu (1972), (31) Hunziker et al. (1998), (32) Jensen et al. (1989), (33) Kammacher et al. (1973), (34) Khosla and Mehra (1973), (35)
Khosla and Sharma (1973), (36) Martel et al. (1997), (37) Miège (1962), (38) Mehra (1982), (39) Mehra and Rememanandan (1973), (40) Mehra and Sharma
(1973), (41) Mehra and Sharma (1975), (42) Morrone et al. (1995), (43) Ahsan et al. (1994), (44) Norrmann et al. (1994), (45) Núñez (1952), (46)
Ozias-Akins et al. (2003), (47) Crins (1991), (48) Pohl and Davidse (1971), (49) Reeder (1967), (50) Reeder (1968), (51) Renno et al. (1995), (52) Rao et al.
(1989), (53) Schmelzer (1997), (54) Sinha et al. (1990), (55) Swaminathan and Nath (1956), (56) Tateoka (1965), (57) Connor (1984), (58) Shanthamma
(1979), (59) Brown and Emery (1958), (60) Sisodia (1970).
SEX ¼ sexual; APO ¼ apomictic.
* Inferred basic chromosome number.
†
Sectional and subsectional treatment sensu Clayton and Renvoize (1986).
However, if P. lanatum is excluded, Pennisetum is paraphyletic with all the species of Cenchrus nested within it. Doust
et al. (2007) developed primers for a novel single copy
nuclear marker that comprises two introns and three exons
of the knotted1 (kn1) gene, and also obtained sequences of
ndhF for four species of Pennisetum, six species of
Cenchrus and some other members of the bristle clade. In
their analyses, Cenchrus formed a monophyletic group
derived from within a paraphyletic Pennisetum. Martel et al.
(2004), using ITS sequences of nuclear ribosomal DNA and
including 13 species of Pennisetum and only one species of
Cenchrus, found C. ciliaris embedded within Pennisetum.
Recently, when studying the phylogenetic relationships of
Setaria and related genera of the bristle clade, Kellogg et al.
(2009) also placed Odontelytrum abyssinicum Hack. in a
clade with Pennisetum and Cenchrus. Odontelytrum has only
a single species, in which an herbaceous involucre that subtends the spikelet may be homologous to the bract-like
cupule in Cenchrus and Pennisetum.
Based on the resolution previously reported for various
genetic markers (Doust et al., 2007; Donadı́o et al., 2009),
two plastid markers (the trnL-F region, comprising the trnL
intron and trnL-F spacer, and the ndhF gene), and one
nuclear marker (knotted1) were selected here to study relationships among Cenchrus, Pennisetum and genera of the bristle
clade. In addition, a morphological matrix was used in a combined analysis. Basic chromosome numbers and reproductive
characters were optimized on the resulting phylogenetic
trees. The present goals were (1) to test the monophyly and circumscription of Pennisetum, Cenchrus and allied genera; (2)
to assess the validity of the traditional taxonomic divisions
of the genus Pennisetum; and (3) to interpret the role that apomixis, polyploidy and hybridization may have played in the
evolution of Pennisetum and Cenchrus.
M AT E R IA L S A ND M E T HO DS
Sampling
For the plastid markers, 51 species (a total of 53 specimens) were
sampled, representing nine species of Cenchrus (56 % of the
total number of species according to Clayton and Renvoize,
1986), 32 of Pennisetum (43 %) and Odontelytrum abyssinicum.
Species representing different genera of the bristle clade
were used as outgroups: Ixophorus unisetus, Paspalidium
geminatum, Setaria palmifolia, S. parviflora, S. sphacelata
and Stenotaphrum secundatum; Rupichloa acuminata was
used as functional outgroup (Appendix 1). Of the 49 sequences
for the trnL-F region, 23 were generated and 26 were downloaded from GenBank. For ndhF, 34 sequences of the 53 were
generated for this study and 19 were added from GenBank
(Appendix 1).
For the nuclear marker (knotted1), 42 taxa were studied:
eight species belonged to Cenchrus and 24 to Pennisetum.
Ixophorus unisetus, Paspalidium jubiflorum, Pseudoraphis
paradoxa, P. spinescens, Setaria palmifolia, S. parviflora,
S. sphacelata, Spinifex sericeus and Stenotaphrum secundatum
were used as outgroups. Trees were rooted using Panicum miliaceum. Seventy-one sequences were generated in this study,
and 33 sequences belonging to the ingroup and 27 to the outgroups were obtained from GenBank (Appendix 1).
DNA extraction and sequencing
The material used for DNA extraction was obtained from
plants collected in wild populations and dried in silica gel or
grown from seeds provided by Plant Gene Resources of
Canada (CN), US Department of Agriculture (PI) and the
Missouri Botanical Garden (MO) (Appendix 1). DNA extraction was via the modified CTAB protocol of Doyle and Doyle
(1987), adapted for small amounts of plant material. When
fresh material was not available, DNA was extracted from herbarium specimens using a Dneasy Plant Mini Kit (QIAGEN
Inc., Hilden, Germany).
Genomic DNA was used as a template to amplify (by PCR)
a plastid fragment containing the trnL (UAA) intron and the
intergenic spacer between the trnL (UAA) 3′ exon and the
trnF (GAA) gene (trnL-F region) and the ndhF gene encoding
a subunit of the respiratory-chain NADH dehydrogenase.
A fragment of the single copy nuclear marker knotted1
(kn1), comprising two introns and three exons, was also amplified (see fig. 2 in Doust et al., 2007). ndhF was amplified in
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
three to five overlapping fragments, depending on the
difficulty of amplification and the quality of the leaf material,
using the following primers: 5F, 536F, 536R, 972F, 972R,
1318F, 1318R and 3R from Olmstead and Sweere (1994),
1660F and 1660R from Aliscioni et al. (2003), and 1821F
and 1821R from Clark et al. (1995). The intron and the intergenic spacer from the trnL-F region were amplified using the
primers c and f from Taberlet et al. (1991) and primers Cii
and Fdw from Giussani et al. (2009). kn1 was amplified in
one fragment with a nested PCR approach, using as a first
set of primers kn1-345F and kn1-622R from Doust et al.
(2007) and a second set of primers, designed specifically for
this paper, kn1-nestF (YGAGTGCCRGAAGGCAAGTA),
kn1-nest3R (ATRTTGGCGCAGCGATCTG) and kn1-nestR
(YCTCGTCRGYTCCTCYCTGA).
PCR reactions were performed in a final volume of 25 mL.
Each reaction contained between 50 and 100 ng of DNA, 1.5
units of Taq polymerase (Invitrogen Life Technologies, São
Paulo, Brazil), 1× PCR buffer, 5 mM MgCl2, 0.2 mM of each
primer and 0.025 mM dNTP each. In species for which these
protocols were unsuccessful, 0.4 % bovine serum albumin
and 1.6 % dimethyl sulfoxide were included as additives and
enhancing agents to increase the yield of PCR reactions.
PCR amplifications followed the following programme: a
first denaturation period at 94 8C for 5 min, followed by 35
cycles of denaturation at 94 8C for 30 s, annealing at 48 8C
for 1 min and extension at 72 8C for 90 s. Final extension at
72 8C for 6 min terminated the reactions. The annealing temperature was varied in some cases to improve amplification.
For kn1, sequences from direct PCR products were used only
when they had ,3 % polymorphisms as indicated by double
peaks in the chromatograms. However, for most species, kn1
was cloned before sequencing. When possible, at least five
clones were sequenced per accession. PCR reactions were run
out on a 1 % Tris-borate-EDTA (TBE) agarose gel, the bands
of DNA were excised, purified using the QIAquick Gel
Extraction Kit Protocol (QIAGEN Inc.) and cloned using the
PGEM-T Easy Vector system (Promega Corp., Madison, WI,
USA). Colonies were picked and incubated overnight in liquid
Luria – Bertani (LB) medium. For checking the insert, plasmids
were extracted and incubated with EcoRI at 37 8C for 2 h.
Digestions were electrophoresed on a 1 % TBE agarose gel
stained with ethidium bromide, and colonies that had incorporated the plasmid were re-grown in liquid LB medium. Plasmids
for sequencing were extracted using the QIAprep Miniprep protocol (QIAGEN Inc.).
PCR products were sequenced by Macrogen, Inc. (Seoul,
Korea). PCR products were cleaned using a Montage PCR
purification kit from Millipore following the manufacturer’s
protocol, and sequencing reactions used ABI PRISM
BigDyeTM Terminator Cycle Sequencing Kits with
AmpliTaq DNA polymerase (Applied Biosystems, Seoul,
Korea). Single-pass sequencing was performed on each template using the same primers used for PCR reactions (see
above), as well as primers e and d from Taberlet et al.
(1991) for the trnL-F region. Unincorporated terminators
were removed by ethanol precipitation. The samples were
resuspended in distilled water and subjected to electrophoresis
in an ABI PRISM 3730XL sequencer (96-capillary type;
Applied Biosystems).
111
Assembly and editing of sequences used the program
Chromas Pro ver. 1.34 (Technelysium Pty, Ltd, Tewantin,
Australia). Sequences of ndhF and kn1 were aligned manually
following alignments performed by Aliscioni et al. (2003)
and Doust et al. (2007), respectively. Sequences of the
trnL-F region were aligned using the program DIALIGN
at BiBiServ (http://bibiserv.techfak.uni-bielefeld.de/dialign/)
(Morgenstern, 2004). DIALIGN is a program that compares
complete segments of sequences, instead of relying on the
sum of individual similarity values or on gap penalties as
optimization criteria; it is thus able to establish small conserved regions that cannot be detected by other alignment
programs (Morgenstern et al., 1998). The alignment was
then adjusted manually. Voucher information and GenBank
accession numbers are provided in Appendix 1. Alignments
and phylogenetic trees were submitted to TreeBASE (http
://purl.org/phylo/treebase/phylows/study/TB2:S10252).
Morphological characters
Fifty-one morphological characters were scored and used in
the phylogenetic analyses (Appendix 2). Characters were taken
from direct examination of herbarium specimens (AAU,
CAMB, K, PRE and SI; Appendix 3), and in some cases information was obtained from the literature (Türpe, 1983; Clayton
et al., 2006). Three to 11 specimens (average, five) were
measured per species including, when possible, the specimen
used to obtain DNA. The matrix is presented as
Supplementary Data, available online, and has been submitted
to TreeBASE (http://purl.org/phylo/treebase/phylows/study/
TB2:S10252).
Phylogenetic analyses
Molecular analyses of the plastid markers (trnL-F region
and ndhF) were performed separately and in combination. A
morphological analysis was conducted separately, and then a
combined analysis of morphology, trnL-F and ndhF was also
performed. The nuclear marker (kn1) was analysed independently using several clones per species.
All analyses were conducted using the program TNT
version 1.1 (Goloboff et al., 2008), with all characters
equally weighted and considered unordered. Gaps were
scored as missing data. In all analyses, parsimony-uninformative characters were deactivated. Heuristic searches were performed using 1000 random addition replicates and tree
bisection – reconnection (TBR) branch swapping, saving ten
trees per replicate. Thereafter, a new search with TBR
branch swapping was performed using the shortest trees
saved in memory. A strict consensus tree was obtained with
all shortest trees found during searches.
Branch support was assessed with 10 000 parsimony jackknife (JK) replicates (Farris et al., 1996), using ten series of
random addition sequences, swapped using TBR and holding
two optimal trees per series. Clades were considered to have
strong branch support when JK ≥ 90 %; moderate support,
JK ≥ 75 % to ,90 %; low support, JK ≤74 %.
Optimization of morphological, cytological and reproductive characters was performed on all most-parsimonious trees
(MPTs) obtained in the plastid analyses and combined
112
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
analysis, using the command ‘Common Synapomorphies’ of
TNT (Goloboff et al., 2008), by which the optimization
shared by all MPTs is represented in the consensus diagram.
RES ULT S
Plastid analysis
The total length of the amplified trnL-F region ranged from 803
to 888 bp. The aligned matrix consisted of 941 characters, only
39 of which were potentially phylogenetically informative.
The matrix included 3.22 % missing data (gaps not included).
Four species had .10 % missing data; of these P. lanatum had
25 %. When aligning the 53 ndhF sequences, only one gap of
6 bp was introduced by Setaria sphacelata, producing a matrix
length of 2055 characters. The total proportion of missing
positions was 2.79 %. Only Pennisetum glaucocladum and
P. hordeoides had .20 % missing data. A total of 116 characters
were potentially parsimony-informative.
There was no contradiction in the placement of the ingroup
taxa between the ndhF and the trnL-F datasets when analysed
separately, and several moderately and strongly supported
clades were recovered in both analyses. Hence, partitions
were assumed to be congruent and they were analysed
together. The combined data matrix consisted of 53 specimens
and 2996 characters in total, with 155 potentially
parsimony-informative characters. Only four species could
not be amplified for trnL-F (Cenchrus agrimonioides,
C. caliculatus, Pennisetum natalense and P. sphacelatum);
however, when excluding these species from the analysis,
neither the topology of the consensus tree nor the branch
support varied significantly, and hence these species were
included in the combined analysis.
The combined plastid analysis produced 2316 trees of 342
steps (CI: 0.53, RI: 0.80); the trees from the combined analysis
are congruent with those from the independent analyses
(Fig. 1A). Figure 2 shows one of the MPTs with branch
lengths drawn to scale. The consensus tree shows
Pennisetum, Cenchrus and Odontelytrum in a strongly supported clade, the ‘PCO clade’ with JK ¼ 97 % (Figs 1A and
2). Only P. lanatum is excluded from the PCO clade; it is
placed in a clade with Ixophorus unisetus (Figs 1A and 2)
with only weak support (JK ¼ 51 %). This clade does not
appear in the trnL-F analysis, in which P. lanatum is placed
in a polytomy outside the PCO clade (tree not shown).
Within the PCO clade, Odontelytrum, P. villosum,
P. trachyphyllum and a clade of seven species of Pennisetum
(P. alopecuroides, P. clandestinum, P. macrourum,
P. natalense, P. orientale, P. sphacelatum and P. thunbergii)
form a polytomy with the remaining species of Pennisetum
and Cenchrus (Fig. 1A).
The relationships among the species of Cenchrus are weakly
supported in clade A (JK ¼ 57 %) together with several
species of Pennisetum. Clade A includes all sampled species
of Cenchrus, plus P. hordeoides, P. massaicum,
P. mezianum, P. pedicellatum, P. polystachion subsp. atrichum, P. polystachion subsp. polystachion, P. purpureum,
P. ramosum and P. setaceum (Fig. 1A). Within clade A, five
species of Cenchrus form a clade (subclade Aa) that comprises
C. pilosus and C. brownii (strongly supported as sister taxa:
JK ¼ 99 %), which are sister to a clade with C. echinatus,
C. myosuroides and C. incertus (JK ¼ 79 %). Cenchrus caliculatus is related to P. setaceum (JK ¼ 62 %), and C. ciliaris and
C. setigerus are closely related (JK ¼ 85 %) with
P. purpureum as their sister group (JK ¼ 93 %). The other
strongly supported group within clade A comprises
P. hordeoides, P. pedicellatum, and both subspecies of
P. polystachion (subclade Ab; JK ¼ 98 %) (Fig. 1A).
Clade B is here represented by P. glaucum (both specimens), P. sieberianum, P. squamulatum and P. violaceum;
all these species form a strongly supported group (JK ¼ 99
%). Clade C includes P. chilense, P. latifolium, P. montanum
and P. tristachyum (JK ¼ 95 %).
Morphological analysis
The parsimony analysis of 51 morphological characters
yielded 249 trees of 345 steps (CI: 0.27, RI: 0.59). The strict
consensus tree showed little resolution, and nodes were
poorly supported (tree not shown). However, the PCO clade
itself is not strongly contradicted and has moderate support
(JK ¼ 81 %). Pennisetum lanatum, contrary to the molecular
results, is situated in a polytomy near the base of the PCO
clade.
Combined analysis of morphology and plastid data
Combining the three datasets (morphology, trnL-F and
ndhF), the analysis yielded 3264 trees of 763 steps with
CI ¼ 0.35 and RI ¼ 0.65 (Fig. 1B). When compared with
the results from the plastid data alone, support for most of
the branches is diminished, probably due to the conflict
added by the morphological characters (Fig. 1A, B). The molecular characters dominate the analysis, as the consensus tree
of the combined analysis has more nodes in common with
the molecular analysis than with the morphological one.
However, P. lanatum, similar to the morphological analysis,
is included as an early branching taxon in the PCO clade
(JK ¼ 98 %).
Lettered clades (A, Aa, Ab, etc.) correspond to clades as
identified in the combined plastid trees. The combined analysis
recovered subclade Aa (JK ¼ 61 %). This subclade is supported by a basic chromosome number of x ¼ 17, although
this character reversed in C. brownii and C. myosuroides
(x ¼ 9, 10; Table 1). Two morphological characters support
this clade: the bristles are fused (char 21, 0 . 2) and the
upper glume is almost as long as the spikelet (char 31, 2 . 3).
Subclade Ab (P. hordeoides, P. pedicellatum and both subspecies of P. polystachion), clade B (both specimens of
Pennisetum glaucum, P. sieberianum, P. squamulatum and
P. violaceum) and clade C (P. chilense, P. latifolium,
P. montanum and P. tristachyum), as in the combined plastid
analysis, are also moderately to strongly supported in the combined analysis (Fig. 1A, B). Subclade Ab is supported by a
single morphological synapomorphy which is the coriaceous
consistency of the upper lemma (char 38, 1 . 2). Species of
clade B are characterized by eight morphological synapomorphies: the upper glume is vestigial, and consequently is
reduced in size (char 30, 2 . 1; char 31, 1 . 0), the apex of
the lower lemma is scaberulous (char 37, 1 . 2), the apex of
A
B
Bristle
clade
Rupichloa acuminata x:13
Ixophorus unisetus
x:9
Stenotaphrum secundatum
?
Paspalidium geminatum
Pennisetum trachyphyllum
Pennisetum villosum
Odontelytrum abyssinicum
45
61
Pennisetum clandestinum
Pennisetum macrourum
86
Pennisetum natalense
Pennisetum alopecuroides
58
Pennisetum thunbergii
48
Pennisetum orientale
81
Pennisetum sphacelatum
97
95
Pennisetum latifolium
Pennisetum tristachyum
x:8 Pennisetum montanum
x:8/9
Pennisetum chilense
55
C
Pennisetum unisetum
Pennisetum flaccidum
Pennisetum glaucocladum
Pennisetum frutescens
Pennisetum unisetum
Pennisetum flaccidum
Pennisetum glaucocladum
Pennisetum basedowii
PCO clade
60
x:7/9
59
31
?
x:7 Pennisetum foermeranum
Pennisetum schweinfurthii
Pennisetum glaucum 1
Pennisetum glaucum 2
x:7
Pennisetum violaceum
99
x:7/9Pennisetum sieberianum
Pennisetum squamulatum
Pennisetum nervosum
Pennisetum frutescens
66
x:8 Pennisetum mezianum
x:5 Pennisetum ramosum
Pennisetum pedicellatum
Pennisetum polystachion subsp. polystachion
Pennisetum hordeoides
98
Pennisetum polystachion subsp. atrichum
x:8
Pennisetum massaicum
Cenchrus agrimonioides
x:7 Pennisetum purpureum
?
57
x:9/17
93
Cenchrus ciliaris x:9
85
Cenchrus setigerus x:9/17
x:9/17
x:9/17
Pennisetum setaceum
x:7
Cenchrus caliculatus
62
Cenchrus pilosus
99
Cenchrus brownii x:9/17
x:17
Cenchrus echinatus
58
Cenchrus incertus
79
x:9/10
Cenchrus myosuroides
85
Setaria sphacelata
Setaria palmifolia
Setaria parviflora
59
Pennisetum lanatum
Pennisetum trachyphyllum
Pennisetum villosum
Odontelytrum abyssinicum
57
Pennisetum clandestinum
Pennisetum macrourum
Pennisetum natalense
Pennisetum alopecuroides
Pennisetum thunbergii
Pennisetum orientale
Pennisetum sphacelatum
94
Pennisetum latifolium
Pennisetum tristachyum
Pennisetum montanum
77
x:8
Pennisetum chilense
B
Ab
A
Aa
Pennisetum foermeranum
Pennisetum schweinfurthii
Pennisetum glaucum 1
x:7
Pennisetum glaucum 2
87
Pennisetum violaceum
99
Pennisetum sieberianum
Pennisetum squamulatum x:7/9
Pennisetum mezianum
Pennisetum ramosum x:5
Pennisetum pedicellatum
52
Pennisetum polystachion subsp. polystachion
99
Pennisetum hordeoides
98
Pennisetum polystachion subsp. atrichum
Pennisetum nervosum
Pennisetum basedowii
25
Pennisetum purpureum x:7
x:8
Pennisetum massaicum
Cenchrus agrimonioides
Cenchrus ciliaris
x:9/17 Cenchrus setigerus
94
56
x:9/17 Pennisetum setaceum
Cenchrus caliculatus
62
Cenchrus pilosus
x:9/17 Cenchrus brownii
86
x:17
Cenchrus echinatus
61
Cenchrus incertus
62
x:9/10 Cenchrus myosuroides
63
x:9
43
91
44
Bristle
clade
98
PCO clade
72
?
56
x:8
19
9
F I G . 1. Phylogenetic relationships of Pennisetum, Cenchrus and Odontelytrum. (A) Strict consensus tree of 2316 MPTs from the combined analysis of the plastid markers (ndhF + trnL-F). (B) Strict
consensus tree of the 3264 MPTs from the combined analysis (ndhF + trnL-F + cytology and morphology). Numbers below branches represent jackknife branch support. Optimization of the basic chromosome number (Appendix 2, character 1) is shown above the branches and, when necessary, next to the species names. Optimization of the degree of fusion of the bristles (Appendix 2, character 21) is shown
as follows: black and white oval, not connate; grey oval, connate below; white oval, connate up to half the total length; black oval, connate up to two-thirds the total length. Bars represent principal clades as
discussed in the text. Pennisetum glaucum 1 corresponds to voucher PI 326520 (sequences downloaded from GenBank) and P. glaucum 2 to voucher Caxambu 375 (see Appendix 1).
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
x:13 Rupichloa acuminata
Paspalidium geminatum
Stenotaphrum secundatum
x:17 Ixophorus unisetus
51
Pennisetum lanatum
Setaria sphacelata
x:9
Setaria palmifolia
96
57
Setaria parviflora
113
114
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
Rupichloa acuminata
Stenotaphrum secundatum
Ixophorus unisetus
Pennisetum lanatum
Paspalidium geminatum
Setaria sphacelata
Setaria palmifolia
Setaria parviflora
Pennisetum trachyphyllum
Pennisetum villosum
Odontelytrum abyssinicum
Pennisetum clandestinum
Pennisetum macrourum
Pennisetum natalense
Pennisetum alopecuroides
Pennisetum thunbergii
Pennisetum orientale
Pennisetum sphacelatum
Pennisetum unisetum
Pennisetum latifolium
Pennisetum tristachyum
Pennisetum montanum
Pennisetum chilense
Pennisetum foermeranum
Pennisetum schweinfurthii
Pennisetum glaucum 2
Pennisetum violaceum
Pennisetum squamulatum
Pennisetum glaucum 1
Pennisetum sieberianum
Pennisetum flaccidum
Pennisetum glaucocladum
Pennisetum basedowii
Pennisetum nervosum
Pennisetum frutescens
Pennisetum ramosum
Pennisetum mezianum
Pennisetum pedicellatum
Pennisetum polystachion subsp. polystachion
Pennisetum hordeoides
Pennisetum polystachion subsp. atrichum
Pennisetum massaicum
Pennisetum purpureum
Cenchrus ciliaris
Cenchrus setigerus
Pennisetum setaceum
Cenchrus calyculatus
Cenchrus agrimonioides
Cenchrus pilosus
Cenchrus brownii
Cenchrus echinatus
Cenchrus incertus
Cenchrus myosuroides
2 steps
F I G . 2. A single tree depicting relative branch lengths for one of the 2316 MPTs based on a combined analysis using two plastid markers: ndhF and trnL-F.
the upper lemma is not acuminate (char 39, 1 . 0/2) and is
ciliate (char 40, 1 . 0), the apex of the upper palea is tridentate (char 44, 1 . 4) and ciliate (char 45, 1 . 0), and anther
tips are penicillate (char 49, 1 . 0). Pennisetum schweinfurthii
is the sister taxon to clade B (JK ¼ 87 %); this relationship is
supported by a basic chromosome number of x ¼ 7, and two
morphological characters: a rounded apex of the lower
lemma (char 36, 1 . 2) and connate styles (char 48, 1 . 0).
Clade C is characterized by two morphological characters: a
membranous-ciliate ligule (char 2, 1 . 2) and an acute apex of
the upper palea (char 44, 1 . 0).
Knotted1 – nuclear data
In all, 131 sequences were used. Pennisetum clandestinum
and P. sieberianum were sequenced directly, whereas for
most other species three to five clones were recovered; only
one or two clones were obtained for P. frutescens,
P. montanum and P. violaceum (Appendix 1). It was not possible to amplify kn1 from the available herbarium material of
Odontelytrum, so its placement is unknown. The total length
of the aligned matrix was 817 bp; sequences varied from
602 bp in one clone of Pennisetum chilense to 747 bp in a
clone of Pseudoraphis spinescens.
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
In total, 315 characters were potentially parsimony-informative,
and the analysis was stopped when it found 30 000 trees
(maximum saved) of 833 steps (CI ¼ 0.53, RI ¼ 0.82); one of
the MPTs with branch lengths drawn to scale is shown in Fig. 3.
Although the consensus of the 30 000 MPTs revealed several
basal polytomies including individual clones, or some clones of
the same species were represented in more than one clade, it was
possible to recover several major strongly supported clades
(Fig. 4).
All species of Cenchrus and Pennisetum, including
P. lanatum, form a monophyletic group (JK ¼ 64 %). Other
major well-supported clades revealed by the analysis are:
clade D (JK ¼ 99 %), which includes three of four clones of
P. thunbergii (3/4) and all clones of P. mezianum (3/3);
clade E (JK ¼ 65 %) with all clones of P. latifolium (3/3)
and P. macrourum (3/3) and separate clones of P. ramosum
(1/3), P. orientale (1/4), P. hordeoides (1/4) and
P. polystachion (2/3); clade F (JK ¼ 79 %), which represents
a subset of the species included in clade A (Fig. 1A),
with C. caliculatus (3/4), C. ciliaris (4/4), C. echinatus
(3/3), C. incertus (1/4), C. myosuroides (2/3), C. pilosus
(4/4), C. setigerus (2/2), P. frutescens (2/2) and P. ramosum
(1/3), but also including clones of P. chilense (1/3),
P. glaucocladum (2/3), P. orientale (1/4) and P. thunbergii
(1/4). Clade G (JK ¼ 94 %) grouped all species included in
clade B (Fig. 1A, B): P. glaucum (PI 326520, sequences
downloaded from GenBank) (2/2) + P. glaucum (Caxambu
375) (3/3), P. squamulatum (4/5), P. violaceum (2/2)
and P. sieberianum (1) and representatives of subclade Ab:
P. hordeoides (3/4), P. polystachion subsp. atrichum (4/4),
P. pedicellatum (1/3) and P. basedowii (4/4). A minor clade,
but strongly to moderately supported, included only two
clones, P. polystachion (1/3) and P. ramosum (1/3), and will
be referred herein as clade H (JK ¼ 88 %).
Comparison of nuclear vs. plastid trees
Pennisetum lanatum. The position of P. lanatum was in dis-
agreement among data partitions. When using the morphological partition alone, P. lanatum is included in the PCO clade
(although with little support), whereas the plastid markers
place P. lanatum outside. However, the combined analysis
included P. lanatum within the PCO clade (Fig. 1A, B).
Clades A – F (Figs 1 and 4). Many of the species in the plastid
clade A (Fig. 1) appear in the nuclear clade F (Fig. 4). Clade F
includes almost all species of Cenchrus, except C. brownii,
and P. frutescens, P. glaucocladum, P. thunbergii,
P. ramosum, P. chilense and P. orientale. Clones of these
species are also related to other groups: P. thunbergii shares
at least one genome with species of clade D, whereas
P. ramosum is allied to species of clades E and
H. Meanwhile, clones of P. chilense and P. orientale fall in
a polytomy at the base of the Pennisetum– Cenchrus clade.
Cenchrus incertus and C. myosuroides are part of clade F,
although several clones are related to C. brownii and
Pennisetum setaceum in a polytomy separated from clade
F. The plastid and combined phylogenetic analyses show
four x ¼ 17 Cenchrus species (C. pilosus, C. brownii,
C. echinatus and C. incertus) and C. myosuroides (x ¼ 9,
115
10) together in subclade Aa. Two clones of P. setaceum are
closely related to clones of C. brownii, C. incertus and
C. myosuroides in the consensus tree of kn1.
Four of six taxa of Pennisetum section Brevivalvula were
grouped in subclade Ab in the plastid and combined analyses:
P. polystachion subsp. polystachion, P. polystachion subsp.
atrichum, P. hordeoides and P. pedicellatum (Fig. 1A, B).
The relationship among these species suggests that they
share a common genome, as shown by the plastid markers.
However, species of subclade Ab present a reticulate pattern
of relationships in the nuclear analysis (kn1). Different
clones of P. polystachion subsp. polystachion linked this
taxon to P. ramosum (clade H, Fig. 4) and to species of
clade E (P. hordeoides, P. latifolium, P. macrourum and
P. orientale).
Clade D (Fig. 4). All clones of Pennisetum mezianum and most
clones of P. thunbergii (3/4) are closely related in the nuclear
phylogenetic tree in clade D, whereas a single clone of
P. thunbergii is included in clade F. However, in the plastid
analysis, P. mezianum and P. massaicum are included in
clade A and P. thunbergii is distantly related and included
in a weakly supported clade with P. alopecuroides,
P. macrourum, P. orientale and P. sphacelatum (Fig. 1A).
Pennisetum mezianum and P. massaicum are morphologically
similar and have a basic chromosome count of x ¼ 8 (Table 1).
Clades C– E (Figs 1 and 4). All kn1 clones of P. macrourum
(3/3), P. latifolium (3/3) and the majority of clones of
P. polystachion subsp. polystachion (2/3) are present in clade
E together with single clones of P. hordeoides, P. orientale
and P. ramosum (Fig. 4). However, these species have apparently acquired their plastids from disparate sources and are distantly related in the plastid phylogenetic tree (Fig. 1A):
P. macrorum is sister to P. natalense, the latter not included
in the nuclear tree, and P. chilense, P. latifolium,
P. montanum, and P. tristachyum (the last of these not included
in kn1) are closely related in the strongly supported clade
C. Meanwhile, P. polystachion is included in the strongly supported subclade Ab with P. polystachion subsp. atrichum,
P. hordeoides and P. pedicellatum.
Clades B – G (Figs 1 and 4). Clade G includes all species of
clade B from the plastid and combined phylogenetic analyses:
P. glaucum, P. sieberianum, P. violaceum and
P. squamulatum, plus species corresponding to subclade Ab
in part: P. hordeoides, P. pedicellatum, P. polystachion
subsp. atrichum and P. basedowii.
Clade H (Fig. 4). This is a small clade that includes individual
kn1 clones of P. ramosum and P. polystachion subsp. polystachion; other clones of both taxa are also related in clade E. The
relationship between these two species is not well resolved by
the plastid and morphological data, although they are closely
related to species of clade A (Fig. 1A, B).
Ploidy
Most species in the Pennisetum/Cenchrus clade are polyploid. In the present sample of species, P. alopecuroides,
P. glaucum, P. ramosum, P. schweinfurthii, P. thunbergii,
P. unisetum and P. violaceum are only known as diploids,
116
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
Panicum miliaceum Ia
Panicum miliaceum Ib
Setaria palmifolia B
Setaria palmifolia Fa
Setaria palmifolia Fb
Ixophorus unisetus 1Ta
Ixophorus unisetus 1Tc
Ixophorus unisetus 1Td
Paspalidium jubiflorum Ea
Paspalidium jubiflorum Eb
Stenotaphrum secundatum la
Stenotaphrum secundatum lb
Setaria parviflora Ga
Setaria sphacelata Ab
Setaria sphacelata Aa
Setaria parviflora Gb
Setaria sphacelata D
Spinifex sericeus 1b
Spinifex sericeus H
Paspalidium jubiflorum Ga
Paspalidium jubiflorum Gb
3 steps
Ixophorus unisetus 2Ob
Ixophorus unisetus 1Tb
Pseudoraphis paradoxa Fa
Pseudoraphis paradoxa Fb
Pseudoraphis spinescens Fa
Pseudoraphis spinescens Fb
Pennisetum orientale d
Pennisetum orientale c
Pennisetum chilense a
Pennisetum chilense b
Pennisetum pedicellatum a
Pennisetum montanum
Pennisetum polystachion subsp. polystachion c
Pennisetum ramosum a
Pennisetum flaccidum 1Ca
Pennisetum flaccidum 1B
Pennisetum flaccidum 2Db
Pennisetum flaccidum 2Da
Pennisetum latifolium c
Pennisetum macrourum b
Pennisetum macrourum c
Pennisetum macrourum a
Pennisetum orientale a
Pennisetum hordeoides a
Pennisetum polystachion subsp. polystachion a
Pennisetum ramosum b
Pennisetum latifolium b
Pennisetum latifolium b
Pennisetum polystachion subsp. polystachion b
Pennisetum setaceum b
Pennisetum glaucocladum b
Cenchrus caliculatus Ab
Pennisetum pedicellatum c
Pennisetum thunbergii a
Pennisetum mezianum b
Pennisetum mezianum a
Pennisetum thunbergii c
Pennisetum mezianum c
Pennisetum thunbergii b
Pennisetum setaceum a
Pennisetum setaceum c
Pennisetum clandestinum
Cenchrus brownii a
Cenchrus brownii b
Cenchrus brownii c
Pennisetum setaceum e
Pennisetum setaceum d
Cenchrus incertus a
Cenchrus incertus d
Cenchrus incertus b
Cenchrus myosuroides D
Pennisetum lanatum D
Pennisetum lanatum E
Pennisetum villosum F
Pennisetum alopecuroides Bb
Pennisetum alopecuroides C
Pennisetum alopecuroides Ba
Pennisetum flaccidum 1Cb
Pennisetum squamulatum c
Pennisetum squamulatum d
Pennisetum squamulatum a
Pennisetum squamulatum e
Pennisetum pedicellatum b
Pennisetum glaucum 1 Eb
Pennisetum violaceum b
Pennisetum violaceum a
Pennisetum glaucum 1 Ea
Pennisetum sieberianum
Pennisetum basedowii c
Pennisetum hordeoides d
Pennisetum basedowii b
Pennisetum glaucum 2 b
Pennisetum glaucum 2 a
Pennisetum hordeoides b
Pennisetum glaucum 2 c
Pennisetum basedowii d
Pennisetum basedowii a
Pennisetum hordeoides c
Pennisetum polystachion subsp. atrichum d
Pennisetum polystachion subsp. atrichum a
Pennisetum polystachion subsp. atrichum b
Pennisetum polystachion subsp. atrichum c
Pennisetum squamulatum b
Pennisetum chilense c
Pennisetum frutescens a
Pennisetum frutescens b
Pennisetum glaucocladum a
Pennisetum glaucocladum c
Pennisetum orientale b
Cenchrus caliculatus Ea
Pennisetum ramosum c
Pennisetum thunbergii d
Cenchrus caliculatus Aa
Cenchrus caliculatus Eb
Cenchrus myosuroides Eb
Cenchrus incertus c
Cenchrus myosuroides Ea
Cenchrus pilosus Eb
Cenchrus pilosus Ea
Cenchrus pilosus Ga
Cenchrus pilosus Gb
Cenchrus ciliaris 2Da
Cenchrus ciliaris 2Db
Cenchrus ciliaris 1Eb
Cenchrus echinatus Ba
Cenchrus echinatus Bb
Cenchrus echinatus D
Cenchrus ciliaris 1Ea
Cenchrus setigerus Fa
Cenchrus setigerus Fb
F I G . 3. A single tree depicting relative branch lengths for one of the 30 000 MPTs based on the nuclear marker knotted1.
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
Panicum miliaceum Ia
Panicum miliaceum Ib
Setaria plamifolia B
Setaria plamifolia Fa
100
Setaria plamifolia Fb
60
Ixophorus unisetus 1Ta
Ixophorus unisetus 1Td
100
Ixophorus unisetus 1Tc
62
Paspalidium jubiflorum Ea
99
Paspalidium jubiflorum Eb
Stenotaphrum secundatum la
72
99
Stenotaphrum secundatum lb
Setaria parviflora Ga
Setaria sphacelata Ab
99
100
Setaria sphacelata Aa
Setaria parviflora Gb
Setaria sphacelata D
Paspalidium jubiflorum Ga
Paspalidium jubiflorum Gb
97
53
Ixophorus unisetus 2Ob
100
Ixophorus unisetus 1Tb
Spinifex sericeus 1b
85 100
Spinifex sericeus H
Pseudoraphis paradoxa Fa
63
Pseudoraphis paradoxa Fb
98
Pseudoraphis spinescens Fa
99
Pseudoraphis spinescens Fb
Pennisetum alopecuroides Ba - Di
Pennisetum flaccidum 1Cb - Di-Po
Pennisetum glaucocladum b
Pennisetum setaceum a - Po-An
Pennisetum setaceum b - Po-An
Cenchrus caliculatus Ab - Po
Pennisetum setaceum c - Po-An
Pennisetum pedicellatum c - Po-An
Pennisetum squamulatum b - Po
Pennisetum villosum F - Di-Po
Pennisetum clandestinum - Po
Pennisetum alopecuroides Bb - Di
Pennisetum alopecuroides C - Di
100
Pennisetum lanatum D - Po
100
Pennisetum lanatum E - Po
Pennisetum orientale d - Di-Po-An
Pennisetum orientale C - Di-Po-An
Pennisetum chilense a
95
Pennisetum chilense b
Pennisetum mezianum b - Di-Po
Pennisetum thunbergii a - Di
Pennisetum mezianum a - Di-Po
99
Pennisetum thunbergii c - Di
Pennisetum mezianum c - Di-Po
Pennisetum thunbergii b - Di
Cenchrus brownii a - Po-An
Cenchrus
brownii b - Po-An
82
72
Cenchrus brownii c - Po-An
Pennisetum setaceum e - Po-An
Pennisetum setaceum d - Po-An
Cenchrus incertus a - Di-An
Cenchrus incertus d - Di-An
53
Cenchrus incertus b - Di-An
Cenchrus myosuroides D - Po-An
Pennisetum pedicellatum a - Po-An
Pennisetum montanum - Po
Pennisetum p subsp. polystachion c - Di-Po-An
88
Pennisetum ramosum a - Di
Pennisetum flaccidum 1Ca - Di-Po
Pennisetum flaccidum 2Da - Di-Po
95
Pennisetum flaccidum 1B - Di-Po
Pennisetum flaccidum 2Db - Di-Po
Pennisetum latifolium c - Po
Pennisetum macrourum b - Po
64
Pennisetum macrourum c - Po
65
52
Pennisetum macrourum a - Po
Pennisetum ramosum b - Di
Pennisetum orientale a - Di-Po-An
Pennisetum hordeoides a - Di-Po
50
Pennisetum p subsp. polystachion a - Di-Po-An
Pennisetum latifolium b - Po
Pennisetum latifolium a - Po
Pennisetum p subsp. polystachion b - Di-Po-An
Pennisetum squamulatum c - Po
Pennisetum squamulatum d - Po
92
Pennisetum squamulatum a - Po
Pennisetum squamulatum e - Po
85
Pennisetum glaucum 2 a - Di
Pennisetum glaucum 2 b - Di
Pennisetum glaucum 2 c - Di
Pennisetum glaucum 1 Ea - Di
94
Pennisetum glaucum 1 Eb - Di
Pennisetum basedowii a - Po
Pennisetum basedowii b - Po
Pennisetum basedowii c - Po
Pennisetum basedowii d - Po
Pennisetum hordeoides b - Di-Po
89
Pennisetum hordeoides c - Di-Po
Pennisetum hordeoides d - Di-Po
Pennisetum pedicellatum b - Po-An
Pennisetum violaceum a - Di
Pennisetum violaceum b - Di
Pennisetum polystachion subsp. atrichum a - Po
Pennisetum sieberianum
Pennisetum polystachion subsp. atrichum d - Po
Pennisetum polystachion subsp. atrichum b - Po
Pennisetum polystachion subsp. atrichum c - Po
61
117
Bristle clade
Pennisetum–Cenchrus
clade
Pennisetum chilense c
Pennisetum frutescens a - An
Pennisetum frutescens b - An
Pennisetum glaucocladum a
Pennisetum
glaucocladum c
52
Pennisetum orientale b - Di-Po-An
Pennisetum ramosum c - Di
Cenchrus caliculatus Ea - Po
Pennisetum thunbergii d - Di
Cenchrus caliculatus Aa - Po
Cenchrus caliculatus Eb - Po
Cenchrus myosuroides Eb - Po-An
Cenchrus incertus c - Di-An
Cenchrus myosuroides Ea - Po-An
Cenchrus pilosus Eb - Di
Cenchrus pilosus Ea - Di
52
Cenchrus pilosus Ga - Di
Cenchrus pilosus Gb - Di
Cenchrus ciliaris 2Da - Di-Po-An
Cenchrus ciliaris 2Db - Di-Po-An
Cenchrus echinatus Ba - Po-An
Cenchrus echinatus D - Po-An
Cenchrus ciliaris 1Eb - Di-Po-An
86
Cenchrus echinatus Ba - Po-An
Cenchrus ciliaris 1Ea - Di-Po-An
Cenchrus setigerus Fa - Di-Po-An
Cenchrus setigerus Fb - Di-Po-An
D
H
E
G
100
79
F
F I G . 4. Strict consensus tree of 30 000 MPTs obtained from parsimony analysis of the nuclear marker knotted1. Numbers below the branches represent jackknife
branch support. Letters following the species names represent different clones; letters in bold represent the reported ploidy/ies: Di, diploid; An, aneuploid; Po,
polyploid. Bars represent principal clades as discussed in the text. Pennisetum glaucum 1 corresponds to voucher PI 326520 (sequences downloaded from
GenBank) and P. glaucum 2 to voucher Caxambu 375 (see Appendix 1).
118
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
although polyploidy cannot be ruled out. At least two copies of
kn1 were retrieved for P. alopecuroides, P. ramosum and
P. thunbergii, indicating polyploidy or duplication of this
gene. In addition, diploid, polyploid and aneuploid plants
have been reported for P. flaccidum, P. hordeoides,
P. massaicum, P. mezianum, P. orientale, P. polystachion
subsp. polystachion, P. purpureum and P. villosum, although
the exact chromosome count for the individual plants
sampled here is unknown. Although P. ramosum and
P. thunbergii are reported to be diploids only (Table 1),
clones appear in at least two places in the phylogenetic tree
(Fig. 4), indicating a polyploid history. Also, P. ramosum is
reported to be apomictic (Table 1), and apomixis is almost
always associated with polyploidy. All species of Cenchrus
are probably of allopolyploid origin, as the lowest chromosome numbers reported are n ¼ 17. All remaining
Pennisetum species are also polyploid.
DISCUSSION
The monophyly of the Pennisetum, Cenchrus and
Odontelytrum clade (PCO clade) is strongly supported by
each marker separately or combined (trnL-F and ndhF), and
by the combined analysis (trnL-F, ndhF and morphology).
The position of P. lanatum is unclear, depending on the evidence included in the analyses; if considering morphology,
or plastid and morphological data together, it is also included
in the PCO clade. From the partition analyses, six unambiguous morphological synapomorphies support the group: spikelet
not disarticulating from the pedicel and falling together with
the bristles as a unit; the pedicel glabrous; the apices of the
lemmas acuminate; the margins of the lemma flat; and a membranaceous – cartilaginous upper anthecium. Doust and
Kellogg (2002) also identified several developmental synapomorphies for the clade: the reduction of the internode on the
secondary axis and on other axes, differential elongation of
the bristles at maturity, and more bristles than spikelets
being initiated in early development. Previous molecular
studies proposed the inclusion of Cenchrus within
Pennisetum (Giussani et al., 2001; Doust and Kellogg, 2002;
Aliscioni et al., 2003; Bess et al., 2005; Doust et al., 2007;
Donadı́o et al., 2009) and also Odontelytrum within
Pennisetum (Kellogg et al., 2009). The position of
P. clandestinum within the PCO clade does not support recognition of the genus Kikuyochloa proposed by Scholz (2006).
Relationships among major clades within Pennisetum – Cenchrus
The ingroup includes a representative sample of the species
treated in the sectional treatment (Stapf and Hubbard, 1934;
Pilger, 1940; Clayton and Renvoize, 1986), but only
Pennisetum section Brevivalvula is supported as monophyletic
by the morphological and plastid analyses (subclade Ab,
Fig. 1A, B). Likewise, Martel et al. (2004), in their ITS analysis, only found sections Brevivalvula and Penicillaria to be
monophyletic, although most of the sections were
under-represented.
The phylogenetic results from independent data sets
(nuclear, plastid and morphology) help to elucidate interspecific
relationships within the complex Pennisetum –Cenchrus –
Odontelytrum. From the plastid phylogenetic trees it was possible to identify monophyletic groups that relate species via
maternal inheritance. Evidence of genetic exchange among
species via biparental inheritance has been provided by the
nuclear marker (kn1). The optimization of morphological, cytological and reproductive characters helps to interpret the principal pattern of relationships among species. In most taxa
investigated, kn1 is a single-copy gene. In polyploids, one
copy per genome is expected, and the gene is thus useful for dissecting the evolutionary history of polyploid species. Sequences
of clones from allopolyploid species are expected to fall in multiple positions in a gene tree, with a set of sequences corresponding to each of the parental genomes.
The position of P. lanatum within the Pennisetum–
Cenchrus clade is reinforced by results of the nuclear marker
(kn1; Fig. 4). Because P. lanatum is a tetraploid, it is possible
that it represents a particularly wide hybridization event, with
the pistillate parent being outside the PCO clade.
Clade A (Fig. 1) was first reported by Donadı́o et al. (2009),
based on data from trnL-F and rpl16, with minor subclades
within it. Both their work and the present study includes
C. brownii, C. ciliaris, C. echinatus, C. incertus, C. myosuroides,
C. pilosus, C. setigerus, P. ramosum, P. polystachion subsp.
polystachion, P. purpureum and P. setaceum within the clade.
In addition, the data here place C. agrimonioides, C. caliculatus,
P. hordeoides, P. massaicum, P. mezianum, P. pedicellatum
and P. polystachion subsp. atrichum within the clade.
Donadı́o et al. (2009) placed P. frutescens and P. flaccidum
within clade A, whereas the here data suggest that they are
outside it. Placements of those two species are not strongly
supported here, so we cannot rule out the possibility that
they belong in the clade. The present results and those
from Donadı́o et al. (2009) use one of the same markers
(trnL-F); discrepancies may be due to differences in phylogenetic signal between ndhF and rpl16, and/or to the addition of
more species.
Cenchrus brownii is clearly related, in plastid and morphological analyses, to other x ¼ 17 Cenchrus taxa. The grouping of four
x ¼ 17 Cenchrus species (C. pilosus, C. brownii, C. echinatus
and C. incertus) has been reported by Donadı́o et al. (2009).
Pennisetum setaceum has been reported as having a basic
chromosome number of x ¼ 9 and 17 (under P. macrostachyon,
Table 1). The x ¼ 17 basic chromosome number and its phylogenetic position revealed that P. setaceum shares at least one
genome with x ¼ 17 species of Cenchrus.
The nuclear phylogenetic analysis supports a larger
sampling for the secondary gene pool of P. glaucum
(Martel et al., 2004). Clade G includes all species of clade
B from the plastid and combined phylogenetic analyses
(Figs 1 and 4) with a basic chromosome number of x ¼ 7
(P. glaucum, P. violaceum and P. squamulatum),
P. sieberianum (basic chromosome number unknown), plus
species corresponding to subclade Ab with a basic chromosome number of x ¼ 9 (P. hordeoides, P. pedicellatum and
P. polystachion subsp. atrichum) and P. basedowii
(Table 1). Following the gene pool classification of Harlan
and de Wet (1971), species of clade G would be part of
the secondary gene pool of P. glaucum, as well as others previously cited for clade B (P. purpureum and P. nervosum;
Donadı́o et al., 2009).
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
Reticulation pattern, polyploidy and apomixis
Figures 3 and 4 show that the entire Pennisetum/Cenchrus
clade is a large polyploid complex. The kn1 tree does not
provide enough resolution to determine the ancestry of all
the polyploids, but a few observations can be made. First,
the history of allopolyploidization is intricate. Cenchrus is
probably the result of an ancient cross between an ancestor
similar to P. ramosum or P. orientale and another species of
Pennisetum. The tree does not identify the other parent with
certainty, but one possibility might be a diploid species
related to P. setaceum.
Speciation has occurred at the polyploid level, as shown by
the mix of polyploids in each of the major clades of the phylogenetic tree. It is possible that gene flow is occurring among
the species. Because crossing barriers are often reduced in
polyploids, this may be expected.
The strongly variable chromosome number found in species
of subclade Ab or Pennisetum section Brevivalvula is a
remarkable fact in favour of reticulation among species of
Cenchrus and Pennisetum. Although the basic chromosome
number was reported as x ¼ 9, P. polystachion was found to
be a hexaploid with, possibly, three different genomes and
little or no pairing among them (Sisodia, 1970). Pennisetum
polystachion subsp. polystachion was reported as 2n ¼ 18,
36, 45, 48, 52, 53, 54 and 63, 2n ¼ 24 under
P. subangustum, and 2n ¼ 32, 56 and 78 under P. setosum
(the last two names now synonyms of P. polystachion). Two
or three distinct kn1 sequences were found in our accession
of P. polystachion subsp. polystachion, suggesting that the
individual plant sequenced was either tetraploid or hexaploid.
In addition, sequences of kn1 for P. polystachion subsp. polystachion are phylogenetically unrelated to those for
P. polystachion subsp. atrichum, even though their plastid
sequences are quite similar. This suggests that the morphological similarity of the two may reflect ancestral gene flow,
despite the distinct nuclear genomes.
Similarly, P. pedicellatum was found to be an allohexaploid
characterized by a low frequency of multivalent formation
(tri-, tetra- and hexavalents), a large number of uni- and bivalents, and 75 % anomalies in anaphase I (Naithani and Sisodia,
1966; Sisodia, 1970). Ploidy in P. pedicellatum was variable:
2n ¼ 36, 45 and 54 with several aneuploid numbers: 24, 30,
32, 35, 42, 48, 52 and 53. Whereas P. pedicellatum is shown
to be related by the plastid and combined analyses to subclade
Ab (Fig. 1A, B), the nuclear marker (Fig. 4) shows it to be
related to clade G (which also includes all x ¼ 7 species of
clade B and representatives of subclade Ab, together with
P. basedowii).
When optimizing the basic chromosome number in the
plastid and combined consensus trees, x ¼ 9 was found to be
plesiomorphic and x ¼ 5, 7, 8, 10 and 17 were derived
(Fig. 1). Similarly, when optimizing the basic chromosome
number on the nuclear phylogenetic trees (kn1), x ¼ 9 is plesiomorphic although several clones of x ¼ 9 species were
included with x ¼ 7 species in clade G.
The nuclear phylogenetic analysis revealed a reticulate
pattern of relationships among species of Pennisetum and
Cenchrus, which is also supported by evidence from cytogenetic studies (aneuploids, hexaploids, uni- and multivalent
119
formations, irregular meiotic behaviour). Hybridization
among species is frequent within this group (Dujardin and
Hanna, 1984b, 1985, 1989; Jauhar, 1981; Marchais and
Tostain, 1997), and sequence relationships suggest that there
are at least three different genomes within Pennisetum –
Cenchrus: the x ¼ 7 genome (clade B, Pennisetum species),
the x ¼ 9 genome (most Pennisetum and Cenchrus species)
and the x ¼ 17 genome (subclade Aa). The origin of the x ¼
17 genome could be the result of a cross between ancestors
of x ¼ 8 and x ¼ 9, or two x ¼ 9 taxa followed by the loss
of one chromosome and, in both cases, followed by diploidization of the ancestral polyploid. Other basic chromosome
numbers would be reductions from x ¼ 9 that appeared independently in P. ramosum (x ¼ 5), P. massaicum,
P. mezianum and P. montanum (x ¼ 8). To resolve species
relationships within Pennisetum – Cenchrus, a group of plants
in which reticulation and introgression are common processes,
would require additional nuclear sequence loci to obtain congruent results and enhance the resolution among taxa.
At least two species of Cenchrus (C. ciliaris and
C. setigerus) and 16 species of Pennisetum have been reported
as facultatively or obligately apomictic (Table 1). Apomixis in
P. squamulatum and C. ciliaris is linked to a single chromosome (Ozias-Akins et al., 1993) that contains a nonrecombining ASGR (Ozias-Akins et al., 1998; Roche et al.,
1999). The conservation of molecular markers linked to apomixis and the close relationship among species of
Pennisetum and Cenchrus support the view of a single event
for the evolution of this trait (Ozias-Akins et al., 2003). It
has been suggested that apomixis characterized subfamily
Panicoideae before its diversification into the present tribes
(Brown and Emery, 1958). Our optimization of the presence
of apomixis in the phylogenetic hypotheses is largely uninformative due to insufficient data. If taxa for which reproductive
behaviour is not reported or unknown are considered apomictic
(Table 1), then apomixis could be considered plesiomorphic,
but if those taxa are sexual, then apomictic species have
appeared several times during the evolution of the
Pennisetum – Cenchrus clade. Because apomixis or the molecular markers linked to apomixis can be transferred to different species through hybridization, it seems more likely that
apomixis is related to the interbreeding history of the group,
rather than appearing independently several times. As a consequence, the acquisition of apomixis through hybridization
within Pennisetum –Cenchrus would be a common mechanism
that allows new genotypes to perpetuate themselves.
Facultative apomixis has been shown to stabilize polyploid
taxa and to permit limited gene flow in other groups of
grasses. In the genera Dichanthium Willemet, Bothriochloa
Kuntze and Capillipedium Stapf (tribe Andropogoneae), de
Wet and Harlan (1970) documented extensive gene flow at
the polyploid level, aided by apomixis. It seems likely that a
similar phenomenon is occurring in Cenchrus/Pennisetum.
Taxonomic implications
The phylogenetic results presented here strongly support the
unification of Cenchrus and Pennisetum, as previously
suggested by Correll and Johnston (1970), and the inclusion
of Odontelytrum, a monotypic genus occurring in Yemen
120
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
and eastern Africa. Pennisetum as currently defined is
paraphyletic, with Odontelytrum and Cenchrus embedded
within it. Optimization of morphological characters within
the PCO clade suggests that no morphological character constitutes a synapomorphy for any of the three genera. Due to the
consistency between the present results and different phylogenetic hypotheses (including morphological, developmental and
multilocus approaches), and the strong support found for the
PCO clade, including the type species of the three genera,
we propose unification of Pennisetum, Cenchrus and
Odontelytrum. Species of Pennisetum and Odontelytrum are
here transferred to Cenchrus (Appendix 4), which has
priority (McNeill et al., 2006). In addition to the morphological and developmental synapomorphies of the PCO clade
(¼ Cenchrus), Cenchrus is here characterized by having one
or several spikelets accompanied by one bristle or surrounded
by an involucre of multiple bristles, free or moderately to considerably fused, or having bristles fused and forming a cup-like
structure (the degree of fusion varying from a small basal disc
to a deep cupule), the consistency of the cupule being rigid or
herbaceous.
Pennisetum, Cenchrus and Odontelytrum have been previously included under Cenchrinae by Clayton and Renvoize
(1986), together with ten other genera bearing bristles. A comprehensive study including all those genera is being conducted
for the tribe Paniceae (Morrone et al., 2008); however, results
are too preliminary to reach any decision on the inclusion of
other genera within Cenchrus as delimited here.
The complex polyploid relationships among the species
shown by the nuclear gene phylogenetic analysis (Figs 3 and 4)
provide another argument for combining Pennisetum and
Cenchrus in a single genus. Biologically, they are clearly
exchanging genes by forming allopolyploids. Their evolution
is reticulate, rather than divergent, and hence is inherently
difficult to incorporate into a hierarchical classification.
The present study also suggests the need for a comprehensive revision of the group to circumscribe infrageneric taxonomic categories based on monophyly, and the
morphological and cytological delimitation of the new groupings. Furthermore, if the intricate pattern of interspecific
relationships within the PCO clade is due to hybridization
and introgression, determining the evolutionary history will
require adding new species and nuclear loci into the analyses.
S U P P L E M E NTA RY D ATA
Supplementary data are available online at www.aob.oxfordjournals.org and consist of the matrix of morphological characters that were used in the phylogentetic analyses.
AC KN OW LED GEMEN T S
This study was supported by ANPCyT (Agencia Nacional de
Promoción Cientı́fica y Técnica, Argentina), grants 13374,
32664 and 01286, and CONICET (Consejo Nacional de
Investigaciones Cientı́ficas y Tecnológicas, Argentina), grant
5453 to O.M.; and US National Science Foundation Grant
DEB-0108501 to E.A.K. Field collections were supported by
the Myndel Botanica Foundation and the National
Geographic Society, USA, grants 7792-05 to O.M. We thank
Prof. M. Ramia, Dr H. Cota-Sánchez, Dr N. Deginani,
Dr F. O. Zuloaga and genetic resources centres [Plant Gene
Resources of Canada, US Department of Agriculture
(USDA) and the Missouri Botanical Garden] for providing
plant material. We thank one anonymous reviewer,
R. J. Soreng and the Editors for their helpful comments and
suggestions on the manuscript.
L I T E R AT U R E C I T E D
Ahsan SMN, Vahidy AA, Ali SI. 1994. Chromosome numbers and incidence
of polyploidy in Panicoideae (Poaceae) from Pakistan. Annals of the
Missouri Botanical Garden 81: 775– 783.
Akenova ME, Chehheda HR. 1981. Morphology, cytology and forage potential of Pennisetum americanum (L.) K. Schum.×P. purpureum Schum.
amphidiploids. Euphytica 30: 397– 404.
Akiyama Y, Goel S, Chen Z, Hanna WW, Ozias-Akins P. 2006. Pennisetum
squamulatum: is the predominant cytotype hexaploid or octaploid?
Journal of Heredity 97: 521 –524.
Aliscioni SS, Giussani LM, Zuloaga FO, Kellogg EA. 2003. A molecular
phylogeny of Panicum (Poaceae: Paniceae): tests of monophyly and phylogenetic placement within the Panicoideae. American Journal of Botany
90: 796 –821.
Avdulov NP. 1931. Karyo-sistematischen Untersuchungen der Familie
Gramineen. Trudy po Prikladnoi Botanike, Genetike i Selektsii 44:
1 –428.
Bess EC, Doust AN, Kellogg EA. 2005. A naked grass in the ‘Bristle Clade’:
a phylogenetic and developmental study of Panicum section Bulbosa
(Paniceae: Poaceae). International Journal of Plant Sciences 166:
371– 381.
Bir SS, Sahni M. 1986. SOCGI plant chromosome number reports – IV.
Journal of Cytology and Genetics 1: 152– 154.
Bir SS, Sahni M. 1987. Chromosomal and morphological variations in grasses
of Punjab. Journal of Cytology and Genetics 22: 12–22.
Brown WV. 1950. A cytological study of some Texas Gramineae. Bulletin of
the Torrey Botanical Club 77: 63– 76.
Brown WV, Emery WH. 1958. Apomixis in the Gramineae: Panicoideae.
American Journal of Botany 45: 253–263.
Brunken JN. 1977. A systematic study of Pennisetum sect. Pennisetum
(Gramineae). American Journal of Botany 2: 161– 167.
Brunken JN. 1979. Cytotaxonomy and evolution in Pennisetum section
Brevivalvula (Gramineae) in tropical Africa. Botanical Journal of the
Linnean Society 79: 37–49.
Burton GW. 1942. A cytological study of some species in the tribe Paniceae.
American Journal of Botany 29: 355–361.
Chase A. 1921. The Linnaean concept of pearl millet. American Journal of
Botany 8: 41–49.
Chatterji AK, Timothy DH. 1969. Microsporogenesis and embryogenesis in
Pennisetum flaccidum Griseb. Crop Science 9: 219–222.
Chen SL, Phillips SM. 2006. Cenchrus. In: Wu ZY, Raven PH. eds. Flora of
China, Poaceae, vol. 22. Beijing/St. Louis, MO: Science Press/Missouri
Botanical Garden Press, 552– 553.
Chopanov P, Yurtsev BN. 1976. Chromosome numbers of some grasses of
Turkmenia II. Botanicheskii Zhurnal SSSR 61: 1240– 1244.
Christopher J, Abraham A. 1976. Studies on the cytology and phylogeny of
South Indian grasses. III. Subfamily VI: Panicoideae, tribe Paniceae.
Cytologia 41: 621– 637.
Clark LG, Zhang WP, Wendel JF. 1995. A phylogeny of the grass family
(Poaceae) based on ndhF sequence data. Systematic Botany 20: 436– 460.
Clayton WD. 1972. Gramineae. 101. Pennisetum. In: Hepper FN. ed. Flora of
West Tropical Africa (III). London: Crown Agents, 459–462.
Clayton WD. 1989. Gramineae (Paniceae, Isachneae and Arundinelleae). In:
Launert E, Pope GV. eds. Flora Zambesiaca, vol. 10 (3). Whitstable:
Whitstable Litho Printers Ltd, 1– 231.
Clayton WD, Renvoize SA. 1982. Pennisetum. In: Polhill RM. ed. Flora of
tropical East Africa. Rotterdam: A.A. Balkema, 672–690.
Clayton WD, Renvoize SA. 1986. Genera Graminum. Grasses of the world.
London: Her Majesty’s Stationery Office.
Clayton WD, Harman KT, Williamson H. (2006 onwards). GrassBase –
The Online World Grass Flora. http://www.kew.org/data/grasses-db.
html. Accessed 20 April 2009.
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
Connor HE. 1984. Breeding systems in New Zealand grasses IX: sex ratios in
dioecious Spinifex sericeus. New Zealand Journal of Botany 22:
569– 574.
Correll DS, Johnston MC. 1970. Manual of the vascular plants of Texas.
Texas: Texas Research Foundation, Renner.
Crins WJ. 1991. The genera of Paniceae (Gramineae: Panicoideae) in the
southeastern United States. Journal of the Arnold Arboretum,
Supplementary Series 1: 171– 312.
Davidse G, Pohl RW. 1972. Chromosome numbers and notes on some Central
American grasses. Canadian Journal of Botany 50: 273– 283.
Davidse G, Pohl RW. 1974. Chromosome numbers, meiotic behavior, and
notes on tropical American grasses. Canadian Journal of Botany 52:
317– 328.
Davidse G, Pohl RW. 1978. Chromosome numbers of Tropical American
grasses (Gramineae). Annals of the Missouri Botanical Garden 65:
637– 649.
DeLisle D. 1963. Taxonomy and distribution of the genus Cenchrus. Iowa
State Journal of Science 37: 259–351.
DeLisle D. 1964. Chromosome numbers in Cenchrus (Gramineae). American
Journal of Botany 51: 1133– 1134.
Donadı́o S, Giussani LM, Kellogg EA, Zuloaga FO, Morrone O. 2009. A
preliminary molecular phylogeny of Pennisetum and Cenchrus
(Poaceae-Paniceae) based on the trnL-F, rpl16 chloroplast markers.
Taxon 58: 392– 404.
Doust AN, Kellogg EA. 2002. Inflorescence diversification in the panicoid
‘Bristle grass’ clade (Paniceae, Poaceae): evidence from molecular phylogenies and developmental morphology. American Journal of Botany 88:
1203–1222.
Doust AN, Penly AM, Jacobs SWL, Kellogg EA. 2007. Congruence, conflict
and polyploidization shown by nuclear and chloroplast markers in the
monophyletic ‘bristle clade’ (Paniceae, Panicoideae, Poaceae).
Systematic Botany 32: 531 –544.
Doyle JJ, Doyle JL. 1987. A rapid DNA isolation procedure for small quantities of fresh leaf tissue. Phytochemical Bulletin 19: 11– 15.
Dujardin M. 1979. Additional chromosome numbers and meiotic behavior in
tropical African grasses from western Zaire. Canadian Journal of Botany
57: 864 –876.
Dujardin M, Hanna W. 1984a. Cytogenetics of double cross hybrids between
Pennisetum americanum – P. purpureum amphiploids and
P. americanum × Pennisetum squamulatum interspecific hybrids.
Theoretical and Applied Genetics 69: 97– 100.
Dujardin M, Hanna W. 1984b. Microsporogenesis, reproductive behavior,
and fertility in five Pennisetum species. Theoretical and Applied
Genetics 67: 197– 201.
Dujardin M, Hanna W. 1985. Cytology and reproduction of reciprocal backcrosses between pearl millet and sexual and apomictic hybrids of pearl
millet × Pennisetum squamulatum. Crop Science 25: 59–62.
Dujardin M, Hanna W. 1989. Crossability of pearl millet with wild
Pennisetum species. Crop Science 29: 77–80.
Duvall MR, Noll JD, Minn AH. 2001. Phylogenetics of Paniceae (Poaceae).
American Journal of Botany 88: 1988– 1992.
Emery WHP. 1957. A study of reproduction in Setaria macrostachya and its
relatives in the Southwestern United States and Northern Mexico. Bulletin
of the Torrey Botanical Club 84: 106–121.
Farris JS, Albert VA, Källersjö M, Lipscomb D, Kluge AG. 1996.
Parsimony jackknifing outperforms neighbor-joining. Cladistics 12:
99–124.
Filgueiras TS. 1984. O gênero Cenchrus L. no Brasil (Gramineae:
Panicoideae). Acta Amazonica 14: 95– 127.
Giussani LM, Cota-Sánchez H, Zuloaga FO, Kellogg EA. 2001. A molecular phylogeny of the grass subfamily Panicoideae (Poaceae) shows multiple origins of C4 photosynthesis. American Journal of Botany 88:
1993–2012.
Giussani LM, Zuloaga FO, Quarı́n CL, Cota-Sánchez JH, Ubayasena K,
Morrone O. 2009. Phylogenetic relationships in the genus Paspalum
(Poaceae: Panicoideae: Paniceae): an assessment of the Quadrifaria and
Virgata informal Groups. Systematic Botany 34: 32–43.
Goel S, Chen Z, Conner JA, Akiyama Y, Hanna WW, Ozias-Akins P.
2003. Delineation by fluorescence in situ hybridization of a single hemizygous chromosomal region associated with aposporous embryo sac formation in Pennisetum squamulatum and Cenchrus ciliaris. Genetics 163:
1069–1082.
121
Goloboff PA, Farris JS, Nixon KC. 2008. TNT, a free program for phylogenetic analysis. Cladistics 24: 774– 786.
Gómez-Martı́nez R, Culham A. 2000. Phylogeny of the subfamily
Panicoideae with emphasis on the tribe Paniceae: evidence from the
trnLF cpDNA region. In: Jacobs SWL, Everett JE. eds. Grasses: systematics and evolution. Collingwood, Vic.: CSIRO Publishing, 136–140.
Gould FW. 1958. Chromosome numbers in southwestern grasses. American
Journal of Botany 45: 757– 767.
Gould FW. 1965. Chromosome numbers in some Mexican grasses. Boletı́n de
la Sociedad Botánica de Mexico 29: 49–62.
Gould FW. 1968. Chromosome numbers of Texas grasses. Canadian Journal
of Botany 46: 1315–1325.
Gould FW, Soderstom TR. 1967. Chromosome numbers of tropical
American grasses. American Journal of Botany 54: 676– 683.
Gould FW, Soderstrom TR. 1970. Chromosome numbers of some Mexican
and Colombian grasses. Canadian Journal of Botany 48: 1633– 1639.
Gould FW, Soderstrom TR. 1974. Chromosome numbers of some Ceylon
grasses. Canadian Journal of Botany 52: 1075– 1090.
Gupta PK, Singh RV. 1977. Variations in chromosomes and flavonoids in
Setaria Beauv. Nucleus 20: 167 –171.
Gustafsson Å. 1946. Apomixis in higher plants. I. The mechanism of apomixis.
Lunds Universitets Årsskrift. N. F. Avd. 2, Bd 42, Nr. 3, pp. 3– 67.
Harlan JR, de Wet JMJ. 1971. Toward a rational classification of cultivated
plants. Taxon 20: 509– 517.
Hodkinson TR, Chase MW, Lledo MD, Salamin N, Renvoize SA. 2002.
Phylogenetics of Miscanthus, Saccharum and related genera
(Saccharinae, Andropogoneae, Poaceae) based on DNA sequences from
ITS nuclear ribosomal DNA and plastid trnL intron and trnL-F intergenic
spacers. Journal of Plant Research 115: 381 –392.
Hrishi NJ. 1952. Studies on the cytogenetics of six species of Pennisetum and
their comparative morphology and anatomy. Genetica 26: 280– 356.
Hsu CC. 1972. Preliminary chromosome studies on the vascular plants of
Taiwan (V). Cytotaxonomy on some monocotyledons. Taiwania 17:
48–65.
Hunziker JH, Zuloaga FO, Morrone O, Escobar A. 1998. Estudios cromosómicos en Paniceae sudamericanas (Poaceae: Panicoideae). Darwiniana
35: 29–36.
Jauhar PP. 1981. Cytogenetics and breeding of pearl millet and related
species. New York: Alan. R Liss, Inc.
Jensen KB, Highnight K, Wipff KJ. 1989. IOPB chromosome data 1.
International Organization of Plant Biosystematists Newsletter 13:
20–21.
Judziewicz EJ. 1990. 187. Poaceae (Gramineae). In: Görts-Van Rijn ARA. ed.
Flora of the Guianas. Series A, Phanaerogams, vol. 8. Königstein: Koeltz
Scientific Books, 1 –127.
Kammacher P, Anoma G, Adjanohoun E, Aké Assi L. 1973. Nombres chromosomiques de Graminées de Côte-d́Ivoire. Candollea 28: 191– 217.
Kellogg EA, Hiser KM, Doust AN. 2004. Taxonomy, phylogeny, and inflorescence development of the genus Ixophorus (Panicoideae: Poaceae).
International Journal of Plant Sciences 165: 1089– 1105.
Kellogg EA, Aliscioni SS, Morrone O, Pensiero J, Zuloaga F. 2009. A phylogeny of Setaria (Poaceae, Panicoideae, Paniceae) and related genera
based on the chloroplast gene ndhF. International Journal of Plant
Sciences 170: 117– 131.
Khosla PK, Mhera PN. 1973. In IOPB chromosome number reports XLII.
Taxon 22: 647–654.
Khosla PK, Sharma ML. 1973. Cytological observations on some species of
Setaria. Nucleus 16: 38–41.
Marchais L, Tostain S. 1997. Analysis of reproductive isolation between
pearl millet (Pennisetum glaucum (L.) R.Br.) and P. ramosum,
P. schweinfurthii, P. squamulatum, Cenchrus ciliaris. Euphytica 93:
97–105.
Martel E, De Nay D, Siljak-Yakovlev S, Brown S, Sarr A. 1997. Genome
size variation and basic chromosome number in pearl millet and fourteen
related Pennisetum species. Journal of Heredity 88: 139– 143.
Martel E, Poncet V, Lamy F, Siljak-Yakolev S, Lejune B, Sarr A. 2004.
Chromosome evolution of Pennisetum species (Poaceae): implications
of ITS phylogeny. Plant Systematics and Evolution 249: 139– 149.
McNeill J, Barrie FR, Burdet HM, et al. 2006. International Code of
Botanical Nomenclature (Vienna). Regnum Vegetabile 146: 1 –568.
Mehra PN. 1982. Cytology of East Indian grasses. India: PN Mehra
Chandigarh.
122
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
Mehra PN, Rememanandan P. 1973. Cytological investigation in West
Himalayan Panicoideae. Cytologia 38: 259–270.
Mehra PN, Sharma ML. 1973. In IOPB chromosome number reports
XXXIX. Taxon 22: 115– 118.
Mehra PN, Sharma ML. 1975. Cytological studies in some central and
eastern Himalayan grasses. II. The Paniceae. Cytologia 40: 75– 89.
Miège J. 1962. Quatrième liste de nombres chromosomiques d‘especies
d́Afrique occidentale. Revue de Cytologie et de Biologie Vegetales 24:
149–164.
Morgenstern B. 2004. DIALIGN: multiple DNA and protein sequence alignment at BiBiServ. Nucleic Acids Research 32: W33–W36.
Morgenstern B, Frech K, Dress A, Werner T. 1998. DIALIGN: finding local
similarities by multiple sequence alignment. Bioinformatics 14: 290–294.
Morrone O, Hunziker JH, Zuloaga FO, Escobar A. 1995. Números cromosómicos en Paniceae sudamericanas (Poaceae: Panicoideae). Darwiniana
33: 53–60.
Morrone O, Aegesen L, Scataglini A, et al. 2008. Phylogeny of the Paniceae
(Poaceae: Panicoideae) integrating chloroplast DNA sequences and morphology. In: The Fourth International Conference on the Comparative
Biology of the Monocotyledons; the Fifth International Symposium on
Grass Systematics and Evolution. Copenhagen: University of
Copenhagen, 43.
Naithani SP, Sisodia KP. 1966. Preliminary meiotic study in Pennisetum pedicellatum Trin. Current Science 35: 343– 344.
Norrmann GA, Quarı́n CL, Killeen TJ. 1994. Chromosome numbers in
Bolivian grasses (Gramineae). Annals of the Missouri Botanical
Garden 81: 768– 774.
Núñez O. 1952. Investigaciones cariosistemáticas en las Gramı́neas
Argentinas de la tribu Paniceae. Revista de la Facultad de Agronomı́a
de La Plata 28: 229–255.
Olmstead RG, Sweere JA. 1994. Combining data in phylogenetic systematics: an empirical approach using three molecular data sets in the
Solanaceae. Systematic Biology 43: 467–481.
Ozias-Akins P. 2006. Apomixis: developmental characteristics and genetics.
Critical Reviews in Plant Sciences 25: 199– 214.
Ozias-Akins P, Lubbers EL, Hanna WW, McNay JW. 1993. Transmission
of the apomictic mode of reproduction in Pennisetum: co-inheritance of
the trait and molecular markers. Theoretical and Applied Genetics 85:
632–638.
Ozias-Akins P, Roche D, Hanna WW. 1998. Tight clustering and hemizygosity of apomixis-linked molecular markers in Pennisetum squamulatum
implies genetic control of apospory by a divergent locus which may have
no allelic form in sexual genotypes. Proceedings of the National Academy
of Sciences USA 95: 5127–5132.
Ozias-Akins P, Akiyama Y, Hanna WW. 2003. Molecular characterization of
the genomic region linked with apomixis in Pennisetum/Cenchrus.
Functional and Integrative Genomics 3: 94–104.
Pilger R. 1940. Gramineae. III: Unterfamilie Panicoideae. In: Engler A, Prantl
K. eds. Die natürlichen pflanzenfamilien, 2nd edn. Leipzig: Engelmann:
1–208.
Pohl RW. 1980. Family No. 15, Gramineae. In: Burger WC. ed. Flora
Costaricensis. Fieldiana: Botany, New Series: 1– 608.
Pohl RW, Davidse G. 1971. Chromosome numbers of Costa Rica grasses.
Brittonia 23: 293–324.
Pohl RW, Davidse G. 1994. Cenchrus. 5. In: Davidse G, Sousa MS, Chater
AO. eds. Flora Mesoamerica, vol. 6. Mexico: Universidad Nacional
Autónoma de Mexico, Sutton and MJ Hufp, 374– 327.
Rao YS, Rao SA, Mengesha MH. 1989. New evidence on the phylogeny of
basic chromosome number in Pennisetum. Current Science 58: 869–871.
Reeder JR. 1967. In IOPB chromosome number reports XI. Taxon 16:
215–222.
Reeder JR. 1968. Notes on Mexican grasses VIII. Miscellaneous chromosome
numbers-2. Bulletin of the Torrey Botanical Club 95: 69– 86.
Renno J-F, Schmelzer GH, de Jong JH. 1995. Variation and geographical
distribution of ploidy levels in Pennisetum section Brevivalvula
(Poaceae) in Burkina Faso, Benin and southern Niger. Plant
Systematics and Evolution 198: 89– 100.
Roche D, Cong P, Chen ZB, et al. 1999. An apospory-specific genomic
region is conserved between buffelgrass (Cenchrus ciliaris L.) and
Pennisetum squamulatum Fresen. Plant Journal 19: 203–208.
Rúgolo de Agrasar ZE, Puglia ML. 2004. Gramı́neas ornamentales. In:
Hurrel JA. ed. Plantas de la Argentina. Silvestres y cultivadas. Buenos
Aires: Editorial LOLA, 1– 336.
Schmelzer GH. 1997. Review of Pennisetum section Brevivalvula (Poaceae).
Euphytica 1: 1 –20.
Scholz H. 2006. Kikuyochloa, genus novum (Poaceae: Paniceae). Feddes
Repertorium 117: 512– 518.
Shanthamma C. 1979. Reproductive behavior of Pennisetum macrostachyum
Benth., and a new basic chromosome number in the genus Pennisetum.
Bulletin of the Torrey Botanical Club 106: 73– 78.
Singh M, Burson BL, Finlayson SA. 2007. Isolation of candidate genes for
apomictic development in buffelgrass (Pennisetum ciliare). Plant
Molecular Biology 64: 673–682.
Sinha R, Bhardwaj PP, Singh RK. 1990. SOCGI plant chromosome number
report-IX. Journal of Cytology and Genetics 25: 140–143.
Sisodia KPS. 1970. Cytological studies on some species in genus Pennisetum.
Theoretical and Applied Genetics 40: 26– 31.
Stapf O, Hubbard CE. 1934. Pennisetum. In: Prain D. ed. Flora of Tropical
Africa. Ashford: L. Reeve & Co. Ltd, 954– 1070.
Swaminathan MS, Nath J. 1956. Two new basic chromosome numbers in the
genus Pennisetum. Nature 178: 1241– 1242.
Taberlet P, Gielly L, Pautou G, Bouvet J. 1991. Universal primers for amplification of three non-coding regions of chloroplast DNA. Plant Molecular
Biology 17: 1105–1109.
Tateoka T. 1965. Chromosome numbers of some east African grasses.
American Journal of Botany 52: 864–869.
Türpe AM. 1983. Las especies sudamericanas del género Pennisetum L.C.
Richard (Gramineae). Lilloa 36: 105– 129.
Watson L, Dallwitz MJ. 1992. The grass genera of the world. Cambridge:
C.A.B. International, University Press.
Webster RD. 1988. Genera of the North American Paniceae (Poaceae:
Panicoideae). Systematic Botany 13: 576 –609.
Wen XS, Ye XL, Li YQ, Chen ZL, Xu SX. 1998. Embryological studies on
apomixis in Pennisetum squamulatum. Acta Botanica Sinica 40:
598– 604.
de Wet JMJ. 1954. Chromosome numbers of a few South African grasses.
Cytologia 19: 97– 103.
de Wet JMJ. 1960. Chromosome numbers and some morphological attributes
of various South African grasses. American Journal of Botany 47: 44–49.
de Wet JMJ, Harlan JR. 1970. Apomixis, polyploidy, and speciation in
Dichanthium. Evolution 24: 270–277.
Wipff JK. 2001. Nomenclature changes in Pennisetum (Poaceae: Paniceae).
Sida 19: 523– 530.
Wipff JK. 2003. Pennisetum Rich. In: Barkworth ME, Capel KM, Long S,
Piep MB. eds. Flora of North America. North of Mexico, vol. 25.
Magnoliophyta: Commelinidae (in part): Poaceae, part 2. New York:
Oxford University Press, 515 –529.
Zuloaga FO, Morrone O. 2003. Cenchrus. In Zulaoga FO, Morrone O,
Davidse G, et al. eds. Catalogue of New World Grasses (Poaceae): III.
Subfamilies
Panicoideae,
Aristidoideae,
Arundinoideae,
and
Danthonioideae. Contributions from the US National Herbarium 46:
144– 150.
Zuloaga FO, Morrone O, Giussani LM. 2000. A cladistic analysis of the
Paniceae: a preliminary approach. In: Jacobs SWL, Everett J. eds.
Grasses: Systematics and Evolution. Melbourne: CSIRO, 123–134.
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
123
APPE NDIX 1
Taxa studied, voucher information for the specimens sequenced here and GenBank accession numbers. ‘– ’ indicates no
sequence for that region. Numbers in parentheses indicate published sequences from GenBank and their reference. Material
grown from seeds. Letters in bold types represent different clones.
GenBank accession
Taxon
Voucher
ndhF
trnL-F
Kn1
–
a: GU561607
b: GU561608
c: GU561609
Aa: EF189760(3)
Ab: EF189762(3)
Ea: EF189761(3)
Eb: EF189763(3)
1Ea: EF189764(3)
1Eb: EF189767(3)
2Da: EF189765(3)
2Db: EF189766(3)
Ba: EF189770(3)
Bb: EF189769(3)
D: EF189768(3)
a: GU561598
b: GU561599
c: GU561600
d: GU5616010
D: EF189772(3)
Ea: EF189771(3)
Eb: EF189773(3)
Ea: EF189777(3)
Eb: EF189775(3)
Ga: EF189774(3)
Gb: EF189776(3)
Fa: EF189778(3)
Fb: EF189779(3)
1Ta: EF189883(3)
1Tb: EF189882(3)
1Tc: EF189884(3)
1Td: EF189885(3)
2Ob EF189880(3)
–
Ia: EF189758(3)
Ib: EF189759(3)
–
Ea: EF189851(3)
Eb: EF189850(3)
Ga: EF189798(3)
Gb: EF189797(3)
Ba: EF189781(3)
Bb: EF189780(3)
C: EF189782(3)
a: GU561550
b: GU561551
c: GU561552
d: GU561553
a: GU561554
b: GU561555
c: GU561556
GU561617
1B: EF189786(3)
1Ca: EF189787(3)
1Cb: EF189783(3)
2Da: EF189785(3)
2Db: EF189784(3)
–
a: GU561557
b: GU561558
Cenchrus agrimonioides Trin.
C. brownii Roem. & Schult.
–
Venezuela, Ramia & Marrero 9349, SI
AY623745(1)
GU561510
–
EU940005(2)
C. caliculatus Cav.
–
EF189886(3)
–
C. ciliaris L.
–
AY029625(4)
EU940006(2)
C. echinatus L.
–
AF499151(5)
EU940007(2)
C. incertus M.A. Curtis
Argentina, Morrone & Giussani 5166, SI
GU561514
EU940008(2)
C. myosuroides Kunth
–
AF499152(5)
EU940009(2)
C. pilosus Kunth
–
EF189887(3)
EU940010(2)
C. setigerus Vahl
–
AF499153(5)
EU940011(2)
Ixophorus unisetus (J. Presl) Schltdl.
–
AY623749(1)
EU939980(2)
Odontelytrum abyssinicum Hack.
Panicum miliaceum L.
Ethiopia, Friis & al. 6699, K
–
GU561512
–
GU561491
–
Paspalidium geminatum (Forssk.) Stapf
Paspalidium jubiflorum (Trin.) Hughes
–
–
AY029662(4)
–
EU939981(2)
–
Pennisetum alopecuroides (L.) Spreng.
–
AY029672(4)
EU939986(2)
P. basedowii Summerh. & C.E. Hubb.
Australia, Pullen 10417, CANB
GU561515
GU561495
P. chilense (E. Desv.) B.D. Jacks. ex R.E. Fr.
Argentina, Zuloaga & al. 8617, SI
GU561516
EU939987(2)
P. clandestinum Hochst. ex Chiov.
P. flaccidum Griseb.
Argentina, Morrone s.n., SI
–
GU561517
AF499150(5)
EU939988(2)
EU939989(2)
P. foermeranum Leeke
P. frutescens Leeke
Namibia, Moss 2017, PRE
Argentina, Deginani 1822, SI
GU561511
GU561519
GU561496
EU939990(2)
Continued
124
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
APPENDIX Continued
GenBank accession
Taxon
Voucher
ndhF
trnL-F
P. glaucocladum Stapf & C.E. Hubb.
Botswana, Smith 2403, PRE
GU561520
GU561497
P. glaucum (L.) R. Br. (1)
–
AF499149(5)
EU939991(2)
P. glaucum (L.) R. Br. (2)
Brasil, Caxambu 375, MBM
GU561521
GU561498
P. hordeoides (Lam.) Steud.
Nepal, Staiton & al. 8844, K
GU561522
GU561499
P. lanatum Klotzsch
India, Bohr 9207, K
India, Siddigi 1053, K
GU561523
–
–
GU561500
P. latifolium Spreng.
Uruguay, Morrone 5231, SI
GU561524
EU939993(2)
P. macrourum Trin.
CN 87800*
GU561525
AY116266(7)
P. massaicum Stapf
P. mezianum Leeke
Kenya, Greenway & Kanuri 12834, K
PI 214061*
GU561526
GU561527
GU561501
GU561502
P. montanum (Griseb.) Hack.
P. natalense Stapf
P. nervosum (Nees) Trin.
P. orientale Rich.
–
South Africa, Strey 10968, K
Argentina, Morrone 5329, SI
CN 84066*
AY188498(6)
GU561528
GU561529
GU561530
EU939994(2)
–
EU939996(2)
GU561503
P. pedicellatum Trin.
CN 87902*
GU561531
GU561504
P. polystachion subsp. polystachion (L.) Schult.
Bolivia, Morrone & Belgrano 5060, SI
GU561533
EU939997(2)
P. polystachion subsp. atrichum (Stapf & C.E. Hubb.)
Brunken
Tanzania, Bjornstad 1704, K
GU561532
GU561505
P. purpureum Schumach.
P. ramosum (Hochst.) Schweinf.
Argentina, Morrone & al. 4473, SI
CN84079*
GU561534
GU561535
EU939999(2)
EU929056
P. schweinfurthii Pilg.
P. setaceum (Forssk.) Chiov.
Ethiopia, Friis & al. 7745, K
Argentina, Morrone 5373, SI
GU561536
GU561537
GU561506
EU940000(2)
P. sieberianum (Schltdl.) Stapf & C.E. Hubb.
P. sphacelatum (Schumach.) T. Durand & Schinz
P. squamulatum Fresen.
PI 532675*
South Africa, Smook 5934, PRE
PI 248534*
GU561538
GU561539
GU561540
EU940001(2)
–
EU929057
P. thunbergii Kunth
CN 87791*
GU561541
GU561507
Kn1
a: GU561569
b: GU561570
c: GU561571
Ea: EF189789(3)
Eb: EF189788(3)
a: GU561547
b: GU561548
c: GU561549
a: GU561565
b: GU561566
c: GU561567
d: GU561568
D: EF189791(3)
E: EF189790(3)
a: GU561559
b: GU561560
c: GU561561
a: GU561562, (6)
b: GU561563
c: GU561564
–
a: GU561572
b: GU561573
c: GU561574
GU561579
–
–
a: GU561580
b: GU561581
c: GU561582
d: GU561583
a: GU561584
b: GU561585
c: GU561586
a: GU561587
b: GU561588
c: GU561589
a: GU561612
b: GU561613
c: GU561614
d: GU561615
–
a: GU561590
b: GU561591
c: GU561592
–
a: GU561593
b: GU561594
c: GU561595
d: GU561597
e: GU561596
GU561616
–
a: GU561602
b: GU561603
c: GU561604
d: GU561605
e: GU561606
a: GU561575
b: GU561576
c: GU561577
d: GU561578
Continued
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
125
APPENDIX Continued
GenBank accession
Taxon
Voucher
ndhF
trnL-F
Kn1
–
–
–
F: EF189792(3)
a: GU561610
b: GU561611
Fa: EF189807(3)
Fb: EF189808(3)
Fa: EF189809(3)
Fb: EF189810(3)
–
B: EF189833(3)
Fa: EF189832(3)
Fb: EF189834(3)
Ga: EF189813(3)
Gb: EF189814(3)
Aa: EF189815(3)
P. trachypyllum Pilg.
P. tristachyum (Kunth) Spreng.
P. unisetum (Nees) Benth.
P. villosum R. Br. ex Fresen.
P. violaceum (Lam.) Rich. ex Pers.
Kenya, Bogdan 1151, K
Bolivia, Morrone & al. 4234, SI
Sudan, Friis & Vollesen 129, K
–
CN 88058*
GU561542
GU561543
GU561544
EF189888(3)
GU561545
GU561508
EU940002(2)
EU929058
EU940004(2)
GU561509
Pseudoraphis paradoxa Pilg.
–
–
–
P. spinescens (R. Br.) Vickery
–
–
–
Rupichloa acuminata (Renvoize) Salariato & Morrone
Setaria palmifolia (J. König) Stapf
Brazil, Zuloaga & Morrone s.n., SI
MO 801593– 2
AY029692(4)
AY029680(4)
GU561490
GU561492
S. parviflora (Poir.) Kerguélen
PI 316422
AY029682(4)
GU561493
S. sphacelata (Schumach.) Stapf & C.E. Hubb. ex M.B.
Moss
PI 268145
AY029681(4)
GU561494
Spinifex sericeus R. Br.
–
–
–
Stenotaphrum secundatum (Walter) Kuntze
–
AY029684(4)
EU939985(2)
Ab: EF189817(3)
D: EF189816(3)
H: EF189822(3)
Ib: EF189824(3)
Ia: EF189854(3)
Ib: EF189855(3)
References: (1) Kellogg et al. (2004), (2) Donadı́o et al. (2009), (3) Doust et al. (2007), (4) Giussani et al. (2001), (5) Doust and Kellogg (2002),
(6) Aliscioni et al. (2003), (7) Hodkinson et al. (2002).
APPENDIX 2
Cytological and morphological characters used in the cladistic
analyses and coding states.
1. Chromosome basic number: x ¼ 5 (0), x ¼ 7 (1), x ¼ 8
(2), x ¼ 9 (3), x ¼ 17 (4), x ¼ 13 (5), x ¼ 10 (6). 2. Ligule:
membranous (0), ciliate (1), membranous – ciliate (2). 3.
Contra-ligule: absent (0), present (1). 4. Leaf blade:
flat (0), convolute (1). 5. Spikelets subtended by an
involucre composed of bristles: absent (0), present (1). 6.
Inflorescence: terminal (0), axillary (1). 7. Inflorescencetype: contracted to spiciform (0), open (1). 8. Panicle axis:
scaberulous (0), glabrous (1), pubescent (2). 9. Involucre:
pedicellate (0), sessile (1). 10. Pedicel of the involucre: glabrous (0), pubescent (1), scaberulous (2). 11. Spikelet: pedicellate (0), sessile (1). 12. Disarticulation at the base of the
spikelet: absent (0), present (1). 13. Disarticulation at the
base of the involucre: absent (0), present (1). 14.
Disarticulation at the base of the upper anthecium: absent
(0), present (1). 15. Disarticulation at the base of the
pedicel: absent (0), present (1). This character applies to the
species in which the spikelet or the involucre is pedicellate
and the disarticulation point is between the pedicel and the
rachis. 16. Pedicel of the spikelet: glabrous (0), pubescent
(1), scaberulous (2). 17. Number of bristles: less than 20
(0), more than 21 (1). 18. Bristles: antrorsely scaberulous
(0), retrorsely scaberulous (1). 19. Bristles: all the bristles
plumose (0), some bristles plumose (1), without plumose
bristles (2). 20. Disposition of the bristles: one whorl (0),
two or more whorls (1). 21. Bristles: free (0), connate below
(1), connate up to half the total length (2), connate up to
two-thirds of the total length (3). 22. Length of the bristles:
one conspicuously longer bristle (0), two or more conspicuously longer bristles (1), all the bristles as long as the spikelet
(2), all the bristles longer than the spikelet (3). 23. Fertile spikelets per involucre: one (0), two or more (1). 24. Spikelets:
isomophous (0), heteromorphous (1). 25. Lower floret: sterile
(0), male (1). 26. Lower glume: absent (0), vestigial (1), complete (2). 27. Length of the lower glume: less than 1/3 of the
spikelet (0), between 1/3 and half the spikelet (1), between
half the spikelet and 2/3 (2), more than 2/3 of the spikelet
(3), same length as the spikelet (4). 28. Consistency of the
lower glume: hyaline (0), membranous (1). 29. Apex of the
lower glume: acute (0), acuminate (1), rounded (2). 30.
Upper glume: absent (0), vestigial (1), complete (2). 31.
Length of the upper glume: less than 1/3 of the spikelet
(0), between 1/3 and half the spikelet (1), between half the spikelet and 2/3 (2), more than 2/3 of the spikelet (3), same length
as the spikelet (4). 32. Consistency of the upper glume:
hyaline (0), membranous (1), chartaceous (2). 33. Apex of
the upper glume: acute (0), acuminate (1), rounded (2).
34. Length of the lower lemma: between 1/3 and half the spikelet (0), between half the spikelet and its total length (1),
same length as the spikelet (2). 35. Consistency of the
lower lemma: hyaline (0), membranous (1), chartaceous (2).
36. Apex of the lower lemma: acute (0), acuminate (1),
rounded (2), bidentate (3), tridentate (4). 37. Margin or
126
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
apex of the lower lemma: ciliate (0), glabrous (1), scaberulous (2). 38. Consistency of the upper lemma: membranous
(0), chartaceous (1), coriaceous (2). 39. Apex of the upper
lemma: acute (0), acuminate (1), rounded (2), bidentate (3),
tridentate (4). 40. Margin or apex of the upper lemma:
ciliate (0), glabrous (1). 41. Lower palea: absent (0), vestigial
(1), complete (2). 42. Apex of the lower palea: acute (0), acuminate (1), rounded (2), bidentate (3), tridentate (4). 43.
Margin or apex of the lower palea: ciliate (0), glabrous
(1). 44. Apex of the upper palea: acute (0), acuminate (1),
rounded (2), bidentate (3), tridentate (4). 45. Margin or
apex of the upper palea: ciliate (0), glabrous (1). 46.
Lemma margin: flat (0), involute (1). 47. Lodicules: absent
(0), present (1). 48. Styles: connate (0), free (1). 49. Anther
tip: glabrous (0), penicillate (1). 50. Upper anthecium
texture: smooth (0), rugose (1). 51. Consistency of the
upper anthecium when mature (with caryopsis): crustaceous
(0), membranous – cartilaginous (1).
APPENDIX 3
Taxa studied in the morphological phylogeny and voucher
information.
Cenchrus brownii: Honduras, Montoya 28, SI. Mexico, Ku
and Yam 410, SI. Thailand, Laegaard and Norsangsri 21870,
SI. C. ciliaris: Argentina, Cabrera et al. 31024, SI; Cabrera
et al. 29829, SI. Ecuador, Laegaard 53064, SI. Mexico,
Lizama 1456, SI. C. echinatus: Argentina, Burkart and
Gamerro 21614, SI; Hicken 12972, SI; Venturi 5509, SI.
Thailand, Laegaard 21791, SI. C. incertus: Argentina,
Pozner and Belgrano 173, SI. Brazil, Conrad and Dietrich
2141, SI. C. myosuroides: Argentina, Morrone and Giussani
5162, SI; Burkart 20289, SI; Burkart 22133, SI;
Guaglianone and Tur 2458, SI. C. pilosus: Peru, Sánchez
Vega and Guevara 6217, SI. C. setigerus: Kenya, Verdcourt
2628, SI.
Ixophorus unisetus: Bolivia, Vargas 2101, SI. Mexico,
Zuloaga et al. 7360, SI.
Odontelytrum abyssinicum: Ethiopia, Ash 2595, K; Friis
et al. 6699, K. Tanzania, Greenway and Kanuri 12617,
K. Yemen, Bisset 281, K; Wood 1945, K.
Paspalidium geminatum: Eritrea, Pappi 6829, SI. Ethiopia,
Burger 1135, SI. Tanzania, Dunipes and Jefford s.n., SI.
Pennisetum alopecuroides: Argentina, Rúgolo de Agrasar
2144, SI. P. basedowii: Australia, Pullen 10417, CANB;
Wolfe and Martin 144, CANB; Paijmans 2513, CANB;
Jacobs 1322, CANB; Perry 201, CANB. P. chilense:
Argentina, Kiesling et al. 9467, SI; Krapovickas 3182, SI;
Zuloaga and Deginani 3772, SI; Correa et al. 4477, SI;
Múlgura et al. 1250, SI; Venturi 4891, SI. P. clandestinum:
Argentina, Burkart 18503, SI; Nicora 9248, SI; Villar
26077, SI. P. flaccidum: Pakistan, Duthie 12666, K;
Hartman 167, K; Norris 85, K; Stewart 10010, K;
Winterbottom 202, K. P. foermeranum: Namibia, Ellis 1069,
PRE; Moss and Jacobsen 45, PRE; Sittman 9, PRE; Smook
5182, PRE; Smook 5231, PRE. P. frutescens: Argentina,
Burkart 20204, SI; Cardini 89, SI; Job 1175, SI; Jörgensen
2891, SI. Paraguay, Arenas 1745, SI. P. glaucocladum:
Botswana, Gibbs Russell 2811, PRE; Smith 1694, PRE;
Smith 2403, PRE. Namibia, de Winter and Marais 4761,
PRE. P. glaucum: Argentina, Burkart 514, SI; Burkart
18479, SI. P. hordeoides: India, Adams 3887, K; van der
Maesen 5033, K. Liberia, Baldwin 9942, K. Nepal, Stainton
et al. 8844, K. P. lanatum: India, Bor 9207, K; Duthie s.n.,
K; Wingate s.n., BAA 13627. Pakistan, Siddigi et al. 1053,
K; Stewart 8830A, K; Webster and Nasir 6491,
K. P. latifolium: Argentina, Burkart and Troncoso 26263,
SI; Cabrera et al. 26474, SI; Porta 209, SI; Schwarz 7647,
SI; Zuluaga et al. 5054, SI. P. macrourum: Kenya, Bogdan
3514, K; Bogdan 3637, K. South Africa, Acocks 18652,
PRE; Barker 588, PRE; Fugler 105, PRE; Taylor 9939,
PRE; Victor 954, PRE. Tanzania, Wingfield 59, K; Wingfield
1004, K; Wingfield 914, K. P. massaicum: Kenya, Ament
799, K; Bogdan 896, K; Bogdan 3614, K; Bogdan 2409, K;
Edwars 2987, K; Greenway and Kanuri 12834,
K. P. mezianum: Namibia, Acocks 18046, PRE; Smook
5117, PRE. Tanzania, Greenway 9836, K; Greenway and
Kanuri 11773, K; Raynal 19340, K; Richards 23694, K;
Richards 25202, K. P. montanum: Argentina, Cabrera et al.
20643, SI; Cabrera et al. 34738, SI; Giardelli 998, SI;
Zuloaga 3767, SI. Bolivia, Morrone and Belgrano 4931, SI.
P. natalense: South Africa, Acocks 10122, PRE; Codd 1367,
PRE; Edwards 2031, PRE; Strey 10968, K; Ward 4200,
PRE. P. nervosum: Argentina, Burkart et al. 26853, SI;
Burkart 21094, SI; Jörgensen 2406, SI; Pedersen 8316, SI;
Zuloaga et al 844, SI. P. orientale: Argentina, Rúgolo de
Agrasar 2188, SI. P. pedicellatum: India, Bor 9207,
K. Kenya, Jeffery 538, K. Sudan, Beshir Eff. 429, K; Daws
906, K; Harrison 87, K; Simpson 7295, K. P. polystachion
subsp. polystachion: Bolivia, Laegaard 22323, AAU. Costa
Rica, Herrera 1544, SI. Ecuador, Laegaard 71230, AAU;
Laegaard 71338, AAU; Laegaard 71517, AAU. Tanzania,
Southon 224, SI. Sri Lanka, Comanor 734, SI; Cooray
69091411R, SI. P. polystachion subsp. atrichum: Kenya,
Grant 878, K. Tanzania, Bjornstad 1704, K; Ngoundai 31,
K. P. purpureum: Argentina, Burkart 18502a, SI. Bolivia,
Zuloaga et al. 1444, SI. Costa Rica, Grayum 3433, SI.
Puerto Rico, Nee 44104, SI. P. ramosum: Tanzania, Leippert
5628, SI. P. schweinfurthii: Ethiopia, Friis et al. 7745,
K. Sudan, Jalen 19, K; Sherif 4028, K; Wickens 854,
K. P. setaceum: Argentina, Morrone 5373, SI; Rúgolo de
Agrasar 2145, SI; Rúgolo de Agrasar 2183, SI; Hurrell and
Bazzano 5646, SI. Venezuela, Ramia and Grande 9341, SI.
P. sieberianum: Saudi Arabia, Collenette 7909, K; Cope
166, K; Fernandez 82, K; Fernandez 1276, K. Yemen, Wood
3428, K. P. sphacelatum: Kenya, Stewart 364, K; Thulin
and Tidigs 277, K; Wesche 1685, K. Tanzania, Renvoize and
Abdallah 2403, K; Taylor 10316, K. South Africa, Mohle
234, PRE; Sheepers 1395, PRE; Smook 5803, SI; Smook
5934, PRE; Smook 6682, SI; Victor 1782, PRE.
P. squamulatum: Kenya, Bodgan 1863, K; Bodgan 2418, K;
Bodgan 3833, K; Glover and Samuel 2733, K. Tanzania,
Greenway et al. 13173, K. P. thunbergii: South Africa,
Drews 157, PRE; Du Toit 2491, PRE; Liebenberg 7305,
PRE; Loxton 238, PRE; Pappi 241, SI; Roberts 3290, PRE;
Smook 5028, PRE. P. trachypyllum: Kenya, Bogdan 1151,
K; Faden and Evans 74/710, K. Uganda, Maitland 1390, K;
Snowden 1445, K; Thomas 1155, K. P. tristachyum:
Argentina, Schreiter 4039, SI; Venturi 1349, SI; Williulz
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
225, SI. Bolivia, Buchtien 457, SI. P. unisetum: Ethiopia,
Friis et al. 593, K. Sudan, Friis and Vollesen 129,
K. Unganda, Katende 677, K. Tanzania, Greenway and
Kanuri 15170, K. P. villosum: Argentina, Crespo 33, SI;
Hicken 12965, SI; Rúgolo de Agrasar 2141, SI. Eritrea,
Pappi 1987, SI.
Rupichloa acuminata: Brazil, Zuloaga et al. 4843, SI;
Zuloaga et al. 4766, SI.
Setaria palmifolia: Guatemala, Türckheim 1450, SI.
Philippines, Fénix 117, SI. Venezuela, Zuloaga and Ortiz
4527, SI. S. parviflora: Argentina, Ragonese 2344, SI;
Tivano 394, SI; Vegeti 361, SI. Bolivia, Morrone and
Belgrano 4935, SI. S. sphacelata: Argentina, Morrone et al.,
649, SI; Morrone et al. 5109, SI; Zuloaga and Morrone
7222, SI. Paraguay, Morrone and Pensiero, 565, SI.
Stenotaphrum secundatum: Argentina, Burkart 274, SI;
Burkart 1494, SI; Lanfranchi 74, SI; Rúgolo de Agrasar
1033, SI.
APPENDIX 4.
Nomenclatural changes
Cenchrus americanus (L.) Morrone, comb. nov. Basionym:
Panicum americanum L., Sp. Pl. 1: 56. 1753. LECTOTYPE.
Illustration in Clusius, Rar. Pl. Hist 2: 215. 1601 (lectotype,
designated by Clayton & Renvoize, in Polhill (ed.), Fl.
Trop. E. Africa, Gramineae 3: 672.1982).
Panicum glaucum L., Sp. Pl.: 56. 1753, non Cenchrus
glaucus Mudaliar & Sudaraj, 1957. Pennisetum glaucum (L.)
R. Br., Prodr. 1: 195. 1810. LECTOTYPE: Sri Lanka,
Hermann s.n. (lectotype, BM, designated as holotype by
Rauschert, Feddes Repert 83(9 – 10): 662, 1973 ).
Cenchrus abyssinicus (Hack.) Morrone, comb. nov.
Basionym: Odontelytrum abyssinicum Hack., Oesterr.
Bot. Z. 48: 86. 1898. TYPE: Ethiopia. Gaffat to Debra
Tabor, 2700 m, 1863, Shimper 1121 (holotype, B; isotype, K).
Cenchrus advena (Wipff & Veldkamp) Morrone, comb.
nov. Basionym: Pennisetum advena Wipff & Veldkamp,
Sida 18(4): 1033, f. 1. 1999. TYPE: United States. Texas,
Brazos Co., cultivated at Texas A&M University, 18 Sep
1990, J.K. Wipff 1723 (holotype, L; isotypes, K, MO, US,
UTC).
Cenchrus annuus (Mez) Morrone, comb. nov. Basionym:
Pennisetum annuum Mez, Bot. Jahrb. Syst. 56 (Beibl. 125):
7. 1921. TYPE: Peru. Lima-Oroya, 17 Apr 1910,
A. Weberbauer 5354 (holotype, B; isotype, US).
Cenchrus arnhemicus (F. Muell.) Morrone, comb. nov.
Basionym: Pennisetum arnhemicum F. Muell., Fragm. 7:
109. 1873. TYPE: Australia. Upper river Victoria River,
F. Mueller s.n. (holotype, MEL).
Cenchrus bambusiformis (E. Fourn.) Morrone, comb. nov.
Basionym: Gymnotrix bambusiformis E. Fourn., Mexic. Pl. 2:
48. 1886. Pennisetum bambusiforme (E. Fourn.) Hemsl. ex
B.D. Jacks., Index Kew. 2: 458. 1895. TYPE: Mexico.
Mirador, Mar 1842, J.G. Schaffner338 (holotype, P; isotypes,
P, US-207605).
Cenchrus basedowii (Summerh. & C.E. Hubb.) Morrone,
comb. nov. Basionym: Pennisetum basedowii Summerh. &
C.E. Hubb., Bull. Misc. Inform. Kew 1926: 440. 1926. TYPE:
Australia. King Sound, May River, Basedow 13 (holotype, K).
127
Cenchrus caninus (Reinw. ex Blume) Morrone, comb. nov.
Basionym: Saccharum caninum Reinw. ex Blume, Catal. Hort.
Bogor.: 38. 1823. Pennisetum caninum (Reinw. ex Blume)
Koord., Exkurs.-Fl. Java 1: 140. 1911. SYNTYPES.
Indonesia. Java, Reinwardt s.n., Junghuhn s.n. and Zollinger
s.n. (types not located).
Gymnotrix macrostachys Brongn., Voy. Monde 2(2): 104,
t. 11. 1830, non Cenchrus macrostchyus Hochst. ex Steud.,
1854. Pennisetum macrostachys (Brongn.) Trin., Mém. Acad.
Imp. Sci. Saint-Pétersbourg, Sér. 6, Sci. Math., Seconde Pt.
Sci. Nat. 3, 1(2 –3): 177. 1834. TYPE: ‘Moluccas’ (type not
located).
Cenchrus chilensis (E. Desv.) Morrone, comb. nov.
Basionym: Gymnotrix chilensis E. Desv., Fl. Chile 6: 251,
t. 74. 1853. Pennisetum chilense (E. Desv.) B.D. Jacks. ex
R.E. Fr., Nova Acta Regiae Soc. Sci. Upsal. 1: 172. 1905.
TYPE: Chile, C. Gay s.n. (holotype, P; isotypes, K, W).
Cenchrus clandestinus (Hochst. ex Chiov.) Morrone, comb.
nov. Basionym: Pennisetum clandestinum Hochst. ex Chiov.,
Annuario Reale Ist. Bot. Roma 8: 41, pl. 5, fig. 2. 1903.
TYPE: Ethiopia, Schimper 2084 (holotype, FI; isotypes, G,
K, TUB).
Cenchrus complanatus (Nees) Morrone, comb. nov.
Basionym: Gymnotrix complanata Nees, Bonplandia
(Hanover) 3: 83. 1855. Pennisetum complanatum (Nees)
Hemsl., Biol. Cent.-Amer., Bot. 3(19): 507. 1885. TYPE:
Panama, Seemann 1560 (holotype, BM; isotype,
US-0093598).
Cenchrus compressus (R. Br.) Morrone, comb. nov.
Basionym: Pennisetum compressum R. Br., Prodr.: 195.
1810. TYPE. Australia. New South Wales, R. Brown 6139
(holotype, K).
Panicum alopecuroides L., Sp. Pl. 1: 55. 1753, non
Cenchrus alopecuroides Thunb., 1794. Pennisetum alopecuroides (L.) Spreng., Syst. Veg. 1: 303. 1825. LECTOTYPE:
China, without collector (lectotype, LINN-80.1, designated
by Veldkamp in Cafferty, Jarvis & Turland, Taxon 49(2):
253, 2000).
Alopecurus hordeiformis L., Sp. Pl. 1: 60. 1753. Pennisetum
hordeiforme (L.) Spreng., Syst. Veg 1: 302. 1825, non
Cenchrus hordeiformis Thunb., 1794. LECTOTYPE: India,
Hudson 29 (lectotype, LINN-82.2, designated by Cope in
Cafferty, Jarvis & Turland, Taxon 49(2): 245, 2000).
Cenchrus crinitus (Kunth) Morrone, comb. nov. Basionym:
Gymnotrix crinita Kunth, Nov. Gen. Sp. (quarto ed.) 1: 112.
1815(1816). Pennisetum crinitum (Kunth) Spreng., Syst.
Veg. 1: 302. 1825. TYPE: Mexico. Michoacán, F.W.H.A.
von Humboldt & A.J.A. Bonpland, s.n. (holotype, P).
Cenchrus distachyus (E. Fourn.) Morrone, comb. nov.
Basionym: Gymnotrix distachya E. Fourn., Mexic. Pl. 2: 48.
1886. Pennisetum distachyum (E. Fourn.) Rupr. ex Chase,
Contr. U.S. Natl. Herb. 22(4): 229. 1921. LECTOTYPE:
Mexico. Barranca de San Martin prope Zacuapan, Galeotti
5680 (lectotype, BR, designated by Chase, Contr. U.S. Natl.
Herb. 22(4): 230, 1921).
Cenchrus domingensis (Spreng. ex Schult.) Morrone,
comb. nov. Basionym: Gymnotrix domingensis Spreng. ex
Schult., Mant. 2: 284. 1824. Pennisetum domingense
(Spreng. ex Schult.) Spreng., Syst. Veg. 1: 302. 1825. TYPE:
Santo Domingo, Bertero s.n. (type not located).
128
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
Cenchrus dowsonii (Stapf & C.E. Hubb.) Morrone, comb.
nov. Basionym: Pennisetum dowsonii Stapf & C.E. Hubb.,
Bull. Misc. Inform. Kew 1933: 279. 1933. TYPE: Kenya.
Naivasha District, Aberdares Range, plain of Lake OĺBolossat,
2100 m, W.J. Dowson 562 (holotype, K; isotype, EA).
Cenchrus durus (Beal) Morrone, comb. nov. Basionym:
Pennisetum durum Beal, Grass. N. Amer. 2: 163. 1896.
LECTOTYPE: Mexico. Chihuahua, Potrero Mts., 12 Oct
1886, C.G. Pringle 817 (lectotype MSC, designated by
Chase, Contr. U.S. Natl. Herb. 22(4): 229, 1921; isolectotypes,
CM, MO-2977366, MO-3727999, US-691229).
Cenchrus flaccidus (Griseb.) Morrone, comb. nov.
Basionym: Pennisetum flaccidum Griseb., Gött. Nach. 1868:
86. 1868. TYPE: India. Kashmir, Ladak, 1900 –1300, Nubra
s.n. [Thomson] (holotype, GOET?).
Cenchrus flexilis (Mez) Morrone, comb. nov. Basionym:
Pennisetum flexile Mez, Notizbl. Bot. Gard. Berlin-Dahlem
7: 51. 1917. TYPE: India. Kaschmir, Scinujpur, Clarke
29026 (holotype, B).
Cenchrus foermeranus (Leeke) Morrone, comb. nov.
Basionym: Pennisetum foermeranum Leeke, Z. Naturwiss.
79: 26.1907. SINTYPE: Namibia. Herero-land, Windhoek,
1897, I. Fischer 77; Windhoek, R. Foermer 46 (syntypes, B;
isosyntypes, K).
Cenchrus glaucocladus (Stapf & C.E. Hubb.) Morrone,
comb. nov. Basionym: Pennisetum glaucocladum Stapf &
C.E. Hubb., Bull. Misc. Inform. Kew 1933: 276. 1933.
TYPE: Zimbabwe. Hunyani River, 1410 m, F. Eyles 4903
(holotype, K).
Cenchrus hohenackeri (Hochst. ex Steud.) Morrone, comb.
nov. Basionym: Pennisetum hohenackeri Hochst. ex Steud.,
Syn. Pl. glum. 1: 103. 1854. TYPE: India. Nilgiri Hills, R.F.
Hohenacker 930 (holotype, K; isotypes, L, M, US-978422,
US-1127293, US-3243707).
Cenchrus hordeoides (Lam.) Morrone, comb. nov.
Basionym: Panicum hordeoides Lam., Tabl. Encycl. 1: 170.
1791. Pennisetum hordeoides (Lam.) Steud., Syn. Pl.
Glumac. 1: 103. 1854. TYPE: Sierra Leone, Smeathman s.n.
(holotype, P).
Cenchrus intectus (Chase) Morrone, comb. nov. Basionym:
Pennisetum intectum Chase, Contr. U.S. Natl. Herb. 24(8):
485. 1927. TYPE: Ecuador: Loja: between Loja and San
Lucas, ca. 2500 m, 6 Sep 1923, A.S. Hitchcock 21477 (holotype, US-1163845).
Cenchrus lanatus (Klotzsch) Morrone, comb. nov.
Basionym: Pennisetum lanatum Klotzsch, Bot. Ergebn. Reise
Waldemar: 65, fig. 99. 1862. TYPE: India, Hoffmeister s.n.
(holotype, C?).
Cenchrus latifolius (Spreng.) Morrone, comb. nov.
Basionym: Pennisetum latifolium Spreng., Syst. Veg. 1: 302.
1825. TYPE: Uruguay. Montevideo, F. Sellow s.n. (holotype,
B?).
Cenchrus longissimus (S.L. Chen & Y.X. Jin) Morrone,
comb. nov. Basionym: Pennisetum longissimum S.L. Chen
& Y.X. Jin, Bull. Bot. Res., Harbin 4(1) 65, fig. 2. 1984.
TYPE: China. Guizhou, Duyun Xian, 23 Aug 1930,
Y. Tsiang 6040 (holotype, JSBI).
Cenchrus macrourus (Trin.) Morrone, comb. nov.
Basionym: Pennisetum macrourum Trin., Gram. Panic.: 64.
1826. SINTYPE: South Africa, Link s.n.; Cape of Good
Hope, Swartz s.n. (sintype of Swartz s.n., LE).
Cenchrus massaicus (Stapf ) Morrone, comb. nov.
Basionym: Pennisetum massaicum Stapf, Bull. Misc. Inform.
Kew 1906: 82. 1906. LECTOTYPE: Kenya. Machakos
District, Makindu, Linton 72 (lectotype, K, designated by
Stapf & Hubbard, Bull. Misc. Inform. Kew 1933: 273, 1933).
Cenchrus mezianus (Leeke) Morrone, comb. nov.
Basionym: Pennisetum mezianum Leeke, Z. Naturwiss. 79:
39. 1907. SYNTYPES: Tanzania, Arusha-Moshi, Uhlig
1076, Tanzania/Kenya, Burraberge, Uhlig 35; Kenya,
Makinde River, Hässner 584 (isosyntype of Uhlig 1076, K;
sintype of Uhlig 35, B, isosintype, EA; sintype of Hässner
584, B).
Cenchrus mildbraedii (Mez) Morrone, comb. nov.
Basionym: Pennisetum mildbraedii Mez, Notizbl. Bot. Gart.
Berlin-Dahlem 7: 52. 1917. TYPE: Rwanda. Sabinio to
Mgahinga, Mildbraed 1763 (holotype, B).
Cenchrus monostigma (Pilg.) Morrone, comb. nov.
Basionym: Pennisetum monostigma Pilg., Bot. Jahrb. Syst.
30(1): 120. 1901. SYNTYPES: Cameroon. Zwischen
Manus-Quelle und Kamewrum-Pic, 2800 m, Feb 1891,
Preuss 822; Cameroon. Manus-Quelle, 1891, Preuss 984 (syntypes, B).
Cenchrus occidentalis (Chase) Morrone, comb. nov.
Basionym: Pennisetum occidentale Chase, Contr. U.S. Natl.
Herb. 24(8): 483. 1927. TYPE: Ecuador: Guayas, west of
Guayaquil, 20 Jun 1923, A.S. Hitchcock 19953 (holotype,
US-1163831).
Cenchrus orientalis (Rich.) Morrone, comb. nov.
Basionym: Pennisetum orientale Rich., in Persoon, Syn. Pl.
1: 72. 1805. TYPE: ‘Cenchrus orientalis Willd. (ined.) Hab.
in Oriente.’ (type not located).
Cenchrus pauperus (Nees ex Steud.) Morrone, comb. nov.
Basionym: Pennisetum pauperum Nees ex Steud., Syn. Pl.
Glumac. 1: 102. 1854. TYPE: Ecuador. Galapagos Islands.
Anon. s.n. (holotype, P; isotype, K).
Cenchrus pedicellatus (Trin.) Morrone, comb. nov.
Basionym: Pennisetum pedicellatum Trin., Mem. Acad. Imp.
Sci. Saint-Pétersbourg, Sér. 6, Sci. Math., Seconde Pt. Sci.
Nat. 3,1(2 – 3): 184. 1834. TYPE: Cape Verde Islands,
St. Iago, D. Peters s.n. (holotype, LE-TRIN-1101.01).
Cenchrus pedicellatus subsp. unispiculus (Brunken)
Morrone, comb. nov. Basionym: Pennisetum pedicellatum
Trin. subsp. unispiculum Brunken, Bot. J. Linn. Soc. 79(1):
62. 1979. TYPE: Ghana. Cape Verde Islands, R. Innes
30227 (holotype, PRE; isotype, K).
Cenchrus peruvianus (Trin.) Morrone, comb. nov.
Basionym: Pennisetum peruvianum Trin., Linnaea 10(3):
295. 1836. TYPE: Peru: Andes Peruviae, 1834, E.F. Poeppig
(holotype, LE; isotypes, BM, US).
Cenchrus petiolaris (Hochst.) Morrone, comb. nov.
Basionym: Gymnotrix petiolaris Hochst., Flora 27: 250.
1844. Pennisetum petiolare (Hochst.) Chiov., Annuario
Reale Ist. Bot. Roma 8(3): 324. 1908. TYPE: Ethiopia. Mt.
Scholoda, Schimper 136 (isotype, K).
Cenchrus pilcomayensis (Mez) Morrone, comb. nov.
Basionym: Pennisetum pilcomayense Mez, Bot. Jahrb. Syst.
56(Beibl. 125): 7. 1921. TYPE. Paraguay. In regione cursus
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
inferioris fluminis Pilcomayo, May 1906, T. Rojas 61
(holoype, B; isotypes, P, US-978374).
Pennisetum frutescens Leeke, Z. Naturwiss. 79: 35. 1907,
non Cenchrus frutescens L., 1753. TYPE: Argentina. Chaco,
Fuerte Sarmiento, Dragones, P.G. Lorentz & G.H.E.W.
Hieronymus 584 (holoype, B; isotype, GOET).
Cenchrus polystachios (L.) Morrone, comb. nov.
Basionym: Panicum polystachion L., Syst. Nat. (ed. 10) 2:
870. 1759. Pennisetum polystachion (L.) Schult., Mant. 2:
146. 1824. LECTOTYPE: India, without collector (lectotype,
LINN-80.4, designated by van der Zon, Wageningen Agric.
Univ. Pap. 92– 1: 335, 1992).
Cenchrus polystachios subsp. atrichus (Stapf & C.E.
Hubb.) Morrone, comb. nov. Basionym: Pennisetum atrichum
Stapf & C.E. Hubb., Bull. Misc. Inform. Kew 1933: 282. 1933.
Pennisetum polystachion subsp. atrichum (Stapf & C.E.
Hubb.) Brunken, Bot. J. Linn. Soc. 79(1): 63. 1979. TYPE:
Malawi. Zomba, 1170 m, Manning 4 (holotype, K).
Cenchrus procerus (Stapf ) Morrone, comb. nov.
Basionym: Beckeropsis procera Stapf, Bull. Misc. Inform.
Kew 1933: 272. 1933. Pennisetum procerum (Stapf ).
W.D. Clayton, Kew Bull. 32(3): 580. 1978. TYPE:
Kenya. Nakuru, Hitchcock 25117 (holotype, K; isotype,
BR).
Cenchrus prolificus (Chase), Morrone, comb. nov.
Basionym: Pennisetum prolificum Chase, Contr. U.S. Natl.
Herb. 22(4): 231, fig. 75. 1921. TYPE: Mexico. Veracruz,
Barranca of Metlac, ca. 900 m, 29 Jan 1895, C. G. Pringle
6075 (holotype, US-250836; isotype, MO-2977369).
Cenchrus purpureus (Schumach.) Morrone, comb. nov.
Basionym: Pennisetum purpureum Schumach., Beskr. Guin.
Pl.: 44. 1827. TYPE: Ghana, Thonning 355 (holotype, C;
isotype, BM).
Cenchrus quianningensis (S.L. Zhong) Morrone, comb.
nov. Basionym: Pennisetum quianningense S.L. Zhong, J.S.
SouthW. Agricv. Coll. 1982(4): 75, pl. 1. 1982. TYPE:
China. Sichuan, Qian’ning, 12 Aug 1974, West Sichuan
Veget. Exped. 05820 (holotype, SWAU).
Cenchrus ramosus (Hochst.) Morrone, comb. nov.
Basionym: Gymnotrix ramosa Hochst., Flora 27(16): 252.
1844. Pennisetum ramosum (Hochst.) Schweinf., Beitr. Fl.
Aethiop.: 301. 1867. TYPE: Sudan. Sennaar, T. Kotschy 199
(isotypes, BM, G, K, L, MO).
Cenchrus rigidus (Griseb.) Morrone, comb. nov.
Basionym: Gymnotrix rigida Griseb., Abh. Königl. Ges.
Wiss. Göttingen 19: 263. 1874. Pennisetum rigidum
(Griseb.) Hack., Anales Mus. Nac. Buenos Aires 11:
84. 1904. TYPE: Argentina. Córdoba: Ascochinga,
Apr 1871, P.G. Lorentz 47 (holotype, GOET; isotypes,
CORD, W).
Cenchrus riparius (Hochst. ex A. Rich.) Morrone, comb.
nov. Basionym: Pennisetum riparium Hochst. ex A. Rich.,
Tent. Fl. Abyss. 2: 381. 1851. TYPE: Ethiopia. Adua
(Adoa), G.H.W. Schimper 84 (holotype, P; isotypes, B, BR,
G, K, M, US-1061597).
Cenchrus rupestris (Chase) Morrone, comb. nov.
Basionym: Pennisetum rupestre Chase, Contr. U.S. Natl.
Herb. 24(8): 484. 1927. TYPE: Peru: Matucana, alt. 2400 m,
12 Apr-3 May 1922, J.F. MacBride & W. Featherstone 453
(holotype, US-1161395).
129
Cenchrus sagittatus (Henrard) Morrone, comb. nov.
Basionym: Pennisetum sagittatum Henrard, Blumea Suppl.
1: 229, tab. 16, fig. 26. 1937. TYPE: Bolivia. Sur Yungas,
La Florida, 1700 m, 4 Feb 1932, L.R. Parodi 10069 (holotype,
L; isotypes, BAA, K, US-1539315).
Cenchrus setaceus (Forssk.) Morrone, comb. nov.
Basionym: Phalaris setacea Forssk., Fl. Aegypt.-Arab.: 17.
1775. Pennisetum setaceum (Forssk.) Chiov., Boll. Soc. Bot.
Ital. 1923: 113. 1923. TYPE: Egypt, P. Forsskål s.n.
(isotype, BM).
Cenchrus shaanxiensis (S.L. Chen & Y.X. Jin) Morrone,
comb. nov. Basionym: Pennisetum shaanxiense S.L. Chen &
Y.X. Jin, Bull. Bot. Res., Harbin 4(1): 68, fig. 3. 1984.
TYPE: China. Shaanxi, Luoyang Xian, 870 m, 2 Nov 1958,
C.L. Tang 957 (holotype, JSBI).
Cenchrus sichuanensis (S.L. Chen & Y.X. Jin) Morrone,
comb. nov. Basionym: Pennisetum sichuanense S.L. Chen &
Y.X. Jin, Bull. Nanjing Bot. Gard. 1988 – 1989: 5. 1990.
TYPE: China. Sichuan, Derong Xian, 2000 – 3000 m, c.i.
3366 (type not located).
Cenchrus sphacelatus (Nees) Morrone, comb. nov.
Basionym: Gymnotrix sphacelata Nees, Fl. Afr. Austral. Ill.:
68. 1841. Pennisetum sphacelatum (Nees.) T. Durand &
Schinz, Consp. Fl. Afr. 5: 784. 1894. SYNTYPES: South
Africa. Stormberg, J.F. Drège s.n.; Gekau to Mbashe (Basche),
J.F. Drège s.n; Gekau, J.F. Drège s.n. (isosyntypes, K).
Cenchrus squamulatus (Fresen.) Morrone, comb. nov.
Basionym: Pennisetum squamulatum Fresen., Mus.
Senckenberg. 2: 137. 1837. TYPE: Ethiopia. Semien
(Simen), Rüppell s.n. (holotype, FR).
Cenchrus stramineus (Peter) Morrone, comb. nov.
Basionym: Pennisetum stramineum Peter, Repert. Spec. Nov.
Regni Veg. Beih. 40(1): 71, fig. 37. 1930. TYPE: Tanzania.
Masai District, Ngorongoro, Peter 43215 (holotype, B).
Cenchrus subangustus (Schumach.) Morrone, comb. nov.
Basionym: Panicum subangustum Schumach., Beskr. Guin.
Pl.: 59. 1827. Pennisetum subangustum (Schumach.) Stapf &
C.E. Hubb., Bull. Misc. Inform. Kew 1933: 271. 1933.
TYPE: Ghana. Thonning s.n. (holotype, C).
Cenchrus tempisquensis (R.W. Pohl) Morrone, comb. nov.
Basionym: Pennisetum tempisquense R.W. Pohl, Fieldiana,
Bot. 38(2): 6, fig. 2. 1976. TYPE: Costa Rica. Guanacaste,
8 km N of Hacienda Palo Verde, 14 km WSW of Bagaces,
10 m, 20 Feb 1969, R.W. Pohl & G. Davidse 11725 (holotype,
ISC; isotypes, CR-47189, F, K, UC, US-3055850).
Cenchrus thulinii (S.M. Phillips) Morrone, comb. nov.
Basionym: Pennisetum thulinii S.M. Phillips, Kew Bull.
46(3): 535. 1991. TYPE: Ethiopia. Arussi Prov., Chilalo
awraja, Katar river, ca. 20 km SW of Asella, 2200 m,
M. Thulin 1541 (holotype, K; isotypes, EA, UPS).
Cenchrus thunbergii (Kunth) Morrone, comb. nov.
Basionym: Pennisetum thunbergii Kunth, Révis. Gramin. 1:
50. 1829. TYPE: South Africa, Thunberg s.n. (holotype, UPS).
Cenchrus trachyphyllus (Pilg.) Morrone, comb. nov.
Basionym: Pennisetum trachyphyllum Pilg., Bot. Jahrb. Syst.
30(1): 122. 1901. SINTYPES: Tanzania. Usambara, Lutindi, Jul
1893, C. Holst 3253; Bulua, Sep 12893, C. Holst 5003;
Usambara, Kwai, Oct 1899, 4600 m, Albers 170; Wegen, Sep
1899, Albers 363; Usagara, W.-Uluguru, 4700 m, Stuhlmann
9087 (isosintype of C. Holst 3253, K, M; sintype of Albers 170, B).
130
Chemisquy et al. — Phylogeny of Pennisetum, Cenchrus and Odontelytrum
Cenchrus trisetus (Leeke) Morrone, comb. nov. Basionym:
Pennisetum trisetum Leeke, Z. Naturwiss. 79: 30. 1907.
TYPE: Ethiopia,. Begemeder, Efak, Schimper 1411 (holotype,
B; isotype, K).
Cenchrus unisetus (Nees) Morrone, comb. nov. Basionym:
Gymnotrix uniseta Nees, Fl. Afr. Austral. Ill.: 66. 1841.
Pennisetum unisetum (Nees) Benth., J. Linn. Soc., Bot. 19:
47. 1881. TYPE: South Africa, Durban (Port Natal), J.F.
Drège s.n. (isotypes, K, L, S).
Cenchrus violaceus (Lam.) Morrone, comb. nov.
Basionym: Panicum violaceum Lam., Tabl. Encycl. 1: 169.
1791. Pennisetum violaceum (Lam.) Rich. ex Pers., Syn. Pl.
1: 72. 1805. TYPE: Senegal, D. Rousillon s.n. (holotype, P).
Cenchrus weberbaueri (Mez) Morrone, comb. nov.
Basionym: Pennisetum weberbaueri Mez, Notizbl. Bot. Gart.
Berlin-Dahlem 7: 50. 1917. TYPE: Peru: Dept. Junin,
Tarma, 3000 –3300 m, 10 Feb 1903, A. Weberbauer 2393
(holotype, B).
Elizabeth Kellogg