Aquatic Botany 91 (2009) 279–290
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Aquatic Botany
journal homepage: www.elsevier.com/locate/aquabot
Systematics of the Alismataceae—A morphological evaluation
Samuli Lehtonen *
Department of Biology, University of Turku, FI-20014 Turku, Finland
A R T I C L E I N F O
A B S T R A C T
Article history:
Received 6 April 2009
Received in revised form 4 August 2009
Accepted 5 August 2009
Available online 13 August 2009
The phylogenetic relationships of aquatic plant families Alismataceae and Limnocharitaceae were
investigated by cladistic analysis of morphological and cytological characters. The use of morphological
data allowed much wider taxon sampling than in recent molecular studies, and resulted in several new
hypotheses. Limnocharitaceae was resolved as a paraphyletic group giving rise to the monophyletic
Alismataceae, contradicting with the results from molecular studies. Most of the currently accepted
genera were relatively well supported as monophyletic groups, with polyphyletic Caldesia and
paraphyletic Limnophyton as notable exceptions. Phylogenetic relationships between different genera
remained poorly supported, but it is suggested that the base chromosome number n = 11 is derived from
the plesiomorphic n = 7.
ß 2009 Elsevier B.V. All rights reserved.
Keywords:
Alismataceae
Limnocharitaceae
Morphological data
Phylogenetics
1. Introduction
The Alismataceae are aquatic or semi-aquatic herbs with a
worldwide distribution and are evolutionary closely related to
Limnocharitaceae, Butomaceae and Hydrocharitaceae (Soltis et al.,
2005). Historically, aquatic plants have presented taxonomic
challenges due to convergence, morphological reduction, and
phenotypic plasticity which has also been the case for the
Alismataceae (Les and Haynes, 1995). The family is treated as
having 14 genera (Haynes et al., 1998) and about one hundred
species, but species-level classifications are typically conflicting
among different authors (Rogers, 1983) and generic circumscriptions are considered unsatisfactory (Cook, 1990; Heywood et al.,
2007). Even the limits of the family have remained controversial. It
has been suggested by several authors that Limnocharitaceae is
nested within Alismataceae (e.g. Pichon, 1946; Les et al., 1997;
Chen et al., 2004; Lehtonen and Myllys, 2008), a view not shared by
others (e.g. Haynes and Holm-Nielsen, 1992; Petersen et al., 2006).
Various classifications below the family level have been
proposed as well. Björkqvist (1968) identified three groups of
Alismataceae genera based on flower characters. One group was
composed of genera with bisexual flowers (Alisma, Baldellia,
Caldesia, Damasonium, Echinodorus, Luronium), another contained
genera with polygamous flowers (Limnophyton, Lophotocarpus,
nowadays included in Sagittaria), and the last group contained
genera with unisexual flowers (Burnatia, Wiesneria, Sagittaria).
Argue (1976) classified Alismataceae differently, based on his
* Tel.: +358 2 333 8743; fax: +358 2 333 5730.
E-mail address: samile@utu.fi.
0304-3770/$ – see front matter ß 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.aquabot.2009.08.002
studies of pollen morphology. He recognized three groups: the
‘‘type 1’’ (Caldesia oligococca only), the ‘‘Alisma subtype’’ (including
Alisma, Baldellia, Damasonium, Luronium), and the ‘‘Sagittaria
subtype’’ (‘typical’ Caldesia, Burnatia, Echinodorus, Sagittaria,
Limnophyton, Wiesneria). These pollen types correspond to the
base chromosome numbers of the genera: the group with Alisma
subtype pollen has a base chromosome number of n = 7 or n = 8,
and genera with Sagittaria pollen subtype have a base chromosome
number of n = 11 (Argue, 1976) or n = 10 (Mujawar et al., 2003).
Molecular phylogenetic studies have greatly improved our
understanding on the monocot relationships. It now appears that
Butomaceae is either the closest living relative of Alismataceae–
Limnocharitaceae clade, and this group is the sister lineage of
Hydrocharitaceae (Soltis et al., 2005), or Butomaceae is a sister of
Hydrocharitaceae and they together form a sister clade to
Alismataceae (Chen et al., 2004). However, molecular studies
have been unable to provide a clear picture of evolutionary
relationships within the Alismataceae. The common, and perhaps
most serious, problem with all the molecular studies dealing with
Alismataceae has been their poor taxon sampling. Although the
largest three genera comprising most of the family have been
almost completely sampled in recent genus-targeted molecular
studies (Sagittaria, Keener, 2005; Alisma, Jacobson and Hedrén,
2007; Echinodorus, Lehtonen and Myllys, 2008), none of these
studies adequately sampled members of the non-target genera.
Hence, these studies were unable to resolve evolutionary relationships at the generic level, except that Echinodorus sensu lato was
found to be polyphyletic (Lehtonen and Myllys, 2008). There have
been some broad-scale studies investigating monocot systematics
which have included various Alismataceae genera, however in
these studies, genera are usually represented by just a single
S. Lehtonen / Aquatic Botany 91 (2009) 279–290
280
species, and many genera have remained unsampled (Les et al.,
1997; Chen et al., 2004; Petersen et al., 2006).
It has been well demonstrated that inadequate taxon sampling
may produce erroneous phylogenies (e.g. Zwickl and Hillis, 2002).
Thus, one possible solution to sampling problem is to utilize
morphological characters which have been studied with some
extent for all described taxa. However, morphological characters
hold various problems for phylogenetic inference, especially in
highly plastic aquatic plants. Typically, perhaps most of the
morphological characters can be considered to be ‘continuous’,
although character states are often named and coded in a way to
obscure this fact (Thiele, 1993). This kind of continuously
overlapping data are often deemed as inappropriate for phylogenetic inference (Pimentel and Riggins, 1987; Stevens, 1991),
although it has also been argued that there are no logical reasons to
omit them (e.g. Thiele, 1993; Rae, 1998; Wiens, 2001). Until
recently, computer programs required the data to be coded as
discrete state, thus possessing a further problem for character state
delimitation, but the computer program TNT (Goloboff et al., 2008)
allows character states to be continuous ranges instead of separate
states (Goloboff et al., 2006). TNT treats continuous characters as
additive, and implements Wagner optimization (Farris, 1970) for
them. By this way, the transformation from one state to another
equals the numerical difference between the states (e.g. if one taxa
has 12 stamens and another has 15–24 stamens, the transformation requires 3 steps). If the continuous characters are coded as
ranges which overlap between two taxa, no steps are required for
the transformation from one state to another (e.g. 15–24 stamens
in one taxon vs. 22–28 stamens in another). Hence, if one taxon has
very broad variation in certain character, the character is
effectively uninformative for the taxa, although it may contain
information for other taxa with narrower variation.
In this study the Alismataceae–Limnocharitaceae clade was
phylogenetically examined on the basis of available morphological
and cytological data. Main goals of the study were to test whether
the currently accepted families and genera – which are delimited
on morphological basis – are actually supported as monophyletic
entities by the very same morphological data. Additionally, it is
hoped that a preliminary hypothesis of phylogenetic groups draws
further attention on investigation of poorly defined groups in more
rigorous studies using molecular tools.
2. Materials and methods
2.1. Taxon sampling and classification adopted
In order to test the questioned monophyly of the Alismataceae,
morphological data was obtained from the most recent taxonomic
treatments of varying genera and species from various regions of the
world (Table 1). While a priority was to include as many species as
possible, several species are poorly defined and for some no adequate
character information is available in the literature. Unfortunately,
these species had to be excluded. A total of 113 taxa were included in
this study. Of these, 104 taxa of Alismataceae and 8 species of
Hydrocharitaceae were included in the ingroup while one species,
Butomus umbellatus was used as an outgroup. The coding of
characters and character states were chosen based on characteristics
that prior researchers deemed important within the study group.
2.2. Character sampling and coding
Most of the morphological characters available for the present
study were continuously variable (Appendix A). Nevertheless, in
many cases character states could be delimited on the basis of
discontinuities (e.g. round-triangular), and were accordingly coded
to have discrete states. Yet, large amount of potentially highly
relevant morphological variation (e.g. stamen number) could not
be objectively coded due to overlapping variation. Instead of
arbitrarily delimiting this variation into discrete character states,
the observed variation was coded as ranges from minimum value
to the maximum, and analyzed as such.
In total 77 characters were coded, 10 as continuous characters
(Appendix B) and 67 as having discrete states (Appendix C).
Character state coding was based on some herbarium work and
field experience, but mostly on critical literature review (Table 1).
Continuous overlapping character values were standardized by
log10 transformation, because different characters were measured
on different scales. All the continuous characters coded as such are
treated as additive (Goloboff et al., 2006). Characters were not
differentially weighted, but it should be noted that the cost from
one state to another equals the numeric difference between the
states (Farris, 1990). Multistate characters with a state that could
be viewed as a subset of another state were coded as additive
Table 1
Reference literature for character coding.
Genus
References
Albidella
Alisma
Astonia
Baldellia
Burnatia
Butomus
Butomopsis
Caldesia
Pichon (1946), Charlton (2004), Haynes and Holm-Nielsen (1994)
Oleson (1941), Björkqvist (1967, 1968), Haggard and Tiffney (1997), Haynes and Hellquist (2000), Jacobson and Hedrén (2007)
Aston (1987), Jacobs (1997)
Kaul (1976), Vuille (1988), Cook (1990), Haggard and Tiffney (1997), Charlton (2004), Kozlowski et al. (2008)
Carter (1960), Symoens and Billiet (1975), Symoens (1984), Haggard and Tiffney (1997)
Dahlgren et al. (1985), Charlton (2004).
Cook (1990), Haynes and Holm-Nielsen (1992)
den Hartog (1957), Carter (1960), Ghafoor (1974), Symoens and Billiet (1975), Kaul (1976), Lai (1977), Symoens (1984),
Haggard and Tiffney (1997), Gituru et al. (2002), Liu et al. (2002)
Kaul (1976), Vuille (1987), Haggard and Tiffney (1997), Qing-feng et al. (1997), Haynes and Hellquist (2000), Rich and Nicholls-Vuille (2001),
Charlton (2004)
Heiser and Whitaker (1948), Baldwin and Speese (1955), Kaul (1976), Haynes and Holm-Nielsen (1994), Haggard and Tiffney (1997),
Kasselmann and Petersen (1999), Kasselmann (2001), Costa and Forni-Martins (2003), Lehtonen (2006, 2008)
Small (1909), Haynes and Holm-Nielsen (1994), Kasselmann and Petersen (1999), Jérémie et al. (2001), Lehtonen and Myllys (2008)
Kenton (1982), Dahlgren et al. (1985), Haynes and Holm-Nielsen (1992)
Dahlgren et al. (1985), Haynes and Holm-Nielsen (1992)
den Hartog (1957), Carter (1960), Ghafoor (1974), Symoens and Billiet (1975), Kaul (1976), Symoens (1984), Aston (1987),
Haggard and Tiffney (1997), Jacobs (1997), Kasselmann (2003)
Björkqvist (1961), Kaul (1976), Cook (1990), Haggard and Tiffney (1997), Kay et al. (1999)
den Hartog (1957), Carter (1960), Symoens and Billiet (1975), Symoens (1984), Cook (1990), Charlton (1991)
Oleson (1941), Bogin (1955), Wooten (1973), Kaul (1976), Haynes and Holm-Nielsen (1994), Qing-feng and Jia-kuan (1996),
Haggard and Tiffney (1997), Haynes and Hellquist (2000), Costa and Forni-Martins (2003), Keener (2005)
Carter (1960), Symoens and Billiet (1975), Symoens (1984), Camenish and Cook (1996), Haggard and Tiffney (1997), Charlton (1999),
Mujawar et al. (2003)
Damasonium
Echinodorus
Helanthium
Hydrocleys
Limnocharis
Limnophyton
Luronium
Ranalisma
Sagittaria
Wiesneria
S. Lehtonen / Aquatic Botany 91 (2009) 279–290
(Wilkinson, 1992), and for the chromosome numbers a specific
step-matrix was used. The step-matrix was based on assumption
that multiplication of the chromosome content (polyploidy) would
require one step (e.g. from n = 7 to n = 14 equals one step), as well
as addition or removal of one chromosome (e.g. from n = 7 to n = 8
equals one step). Hence, for example, the change from n = 7 to
n = 11 can take place either via addition of extra chromosomes:
n = 7 ! n = 8 ! . . . ! n = 11 (in total 4 steps), or via polyploidy and
subsequent
reduction
of
chromosomes:
n = 7 ! n = 14 ! n = 13 ! . . . ! n = 11 (in total 4 steps). In some
taxa chromosome numbers are somewhat variable, for example in
Echinodorus and Helanthium base chromosome number appears to
be 2n = 22, but in some populations 2n = 33 has been observed
(Kasselmann and Petersen, 1999; Costa and Forni-Martins, 2004).
As well, Baldellia has been reported to have highly variable
chromosome numbers, although majority of the studies report
2n = 16 (Kozlowski et al., 2008). Taxa with variable chromosome
numbers were coded according to the most common state (e.g.
Baldellia 2n = 16, Echinodorus and Helanthium species with variable
numbers as 2n = 22).
2.3. Cladistic analyses
The data matrix included 113 terminals, and was therefore too
large to be effectively analyzed with simple tree bisection and
281
reconnection (TBR) algorithms (Goloboff, 1999). Therefore, a more
aggressive search strategy using parsimony ratchet (Nixon, 1999)
was employed. To measure the fit of the data to the obtained
phylogeny a jackknife support index (Farris et al., 1996) was
calculated.
Parsimony analyses were performed with TNT (Goloboff et al.,
2008) by completing 10,000 replicates with ratchet (mult = ratchet
replic 10,000 hold 10). The character upweighting during ratchet
perturbations followed default settings. In the jackknife resampling 100 pseudoreplicates were calculated, each analyzed with
100 ratchet replicates (resample jak replications 100 [mult = ratchet replic 100 hold 1]).
3. Results
The analysis resulted in one most parsimonious tree with a
length of 451.190 steps, a consistency index of 0.24 and a retention
index of 0.81. The tree is presented with jackknife support values
and character optimization in Figs. 1–3. Limnocharitaceae is
resolved as a paraphyletic grade giving rise to the monophyletic
Alismataceae. The monophyly of Alismataceae is supported with
100% jackknife support. Most of the currently accepted genera are
supported as monophyletic groups with relatively high jackknife
support values. Exceptions are Limnophyton, which includes
monospecific genus Astonia, and polyphyletic Caldesia. The
Fig. 1. Strict consensus of the two equally parsimonious trees. Non-homoplasious character state changes are marked with black circles, and homoplasious changes with open
circles. Character numbers are given above and derived states below the circles. Grey circles indicate changes in continuous characters, the +/ symbols indicating increase/
decrease in the character. Jackknife support values for the clades are shown in larger numbers above the branches.
282
S. Lehtonen / Aquatic Botany 91 (2009) 279–290
Fig. 2. Continued from Fig. 1.
phylogenetic relationships between genera remain poorly supported.
4. Discussion
Strikingly different hypothesis on Alismataceae phylogeny has
been obtained in molecular studies, possibly due to poor taxon
and character sampling. It appears likely that the controversies in
the molecular phylogenies partly result from the incorrect
rooting, possibly due to long-branch attraction to outgroup
(Bergsten, 2005). For example, the analysis based on most rapidly
evolving sequences (Lehtonen and Myllys, 2008) resulted in
deeper level relationships that were highly different from those
found in analyses of more conservative sequences, which may
indicate that the sequences were giving misleading signal at that
phylogenetic level. As well, the two studies utilizing rbcL gene (Les
et al., 1997; Chen et al., 2004) resulted in apparently incongruent
phylogenies, although the only real difference is in the root
position (Fig. 4).
Whether or not Limnocharitaceae is nested within Alismataceae has remained controversial in molecular studies, but the
monophyly of Limnocharitaceae has not been questioned. In
contrast, the current morphology based phylogeny support the
monophyletic origin of Alismataceae, but Limnocharitaceae is
paraphyletic. Obviously, a well-sampled analysis including molecular data is required to confirm these relationships.
4.1. A review of the Alismataceae classification
Not so many hypothesis for the relationships within
Alismataceae have been postulated, but it appears that the
species with temperate distribution and base chromosome
number n = 7(8) and those with tropical distribution and
n = 11(10) (hereafter n = 7 and n = 11 species) form two distinct
groups. If the rbcL-trees (Les et al., 1997; Chen et al., 2004) are
rooted to have monophyletic Alismataceae, these cytological
groups appear as sister clades, as they do in the mitochondrial
tree (Petersen et al., 2006). In contrast, in the present
morphology based phylogeny the monophyletic n = 11 clade is
derived from a paraphyletic n = 7 group, although the grouping
lacks jackknife support. The currently accepted genera are
shortly discussed below.
4.1.1. Damasonium miller
A genus with a fragmented distribution pattern following
mediterranean climates: one species in California, one species in
Australasia, and three species in western-southern Europe (Rich
and Nicholls-Vuille, 2001). Damasonium has been considered as an
intermediate genus between Alismataceae and Limnocharitaceae
due to the presence of multiovulate carpels in most of the species.
This character appears to be derived and not plesiomorphic in
Damasonium, however. Damasonium californicum is the only
species in the genus with a single ovule, and the species appears
S. Lehtonen / Aquatic Botany 91 (2009) 279–290
283
Fig. 3. Continued from Fig. 2.
to be a sister to rest of the genus. Phylogenetically more recently
diverged species have either two, or in the case of D. polyspermum,
multiple ovules. Studies based on rbcL sequences placed Damasonium close to Alisma, Baldellia and Luronium (Les et al., 1997;
Fig. 4. Phylogenetic relationships within Alismataceae based on recent parsimony
analyses of molecular data: (A) Les et al. (1997), based on rbcL. (B) Chen et al. (2004),
based on rbcL. (C) Petersen et al. (2006), based on cob, atp1, and rbcL. (D) Lehtonen
and Myllys (2008), based on LEAFY, matK, ITS, 5S-NTS, and morphological data.
Chen et al., 2004), a grouping that is at least somewhat consistent
with the morphological results presented here.
4.1.2. Alisma L
A genus of ca. nine species, typically distributed in Northern
Hemisphere (Björkqvist, 1967, 1968; Jacobson and Hedrén, 2007).
A sister relationship with Damasonium is supported here. The
phylogeny of the genus was recently studied with molecular
techniques by Jacobson and Hedrén (2007), but remained partially
ambiguous. Two species groups within diploid species were found
in molecular studies (Jacobson and Hedrén, 2007), of which the A.
gramineum-A. wahlenbergii clade is supported here as well. The
exact origin of polyploid species has remained obscure, and some
species appear to be paraphyletic (Jacobson and Hedrén, 2007).
Clearly, the phylogenetic relationships within the genus are still
poorly understood.
4.1.3. Baldellia Parl
A small genus with two or three species, distributed from
Western Europe to northern Africa (Cook, 1990; Kozlowski et al.,
2008). Baldellia has been considered as a close relative of
Echinodorus (Cook, 1990), but these accounts actually refer to
Helanthium (i.e. Echinodorus in a broad, polyphyletic sense). Both of
the genera (Baldellia and Helanthium) consist of relatively small
plants capable of producing inflorescence stolons, but are unlikely
to be closely related. Cytology and molecular studies support the
close relationship between Baldellia and Alisma. This hypothesis,
however, is not strictly supported by the present analysis: Baldellia
and Luronium are resolved as the early diverging lineages of the
clade composed of species with base chromosome number n = 11.
It should be noted that, even tough the base chromosome number
of Baldellia and Luronium appears to be n = 7, chromosomal
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S. Lehtonen / Aquatic Botany 91 (2009) 279–290
rearrangements have occurred in both genera, since Luronium is
reported to have 2n = 42 (Björkqvist, 1961) and Baldellia 2n = 14–
30 (Kozlowski et al., 2008).
4.1.4. Luronium Raf
A monospecific genus with a European distribution (Cook,
1990). Luronium is morphologically extremely variable, and the
inflorescence can be considered to be partially fertile inflorescence
stolon. Molecular studies have suggested affinity with Damasonium, Baldellia and Alisma, but the morphological data suggests
closer relationship with the n = 11 species.
4.1.5. Helanthium (Benth. and Hook.f.) Engelm. ex J.G.Sm
A genus with Western Hemisphere distribution and highly
variable views upon the number of species. Higher species
numbers were proposed earlier (four species listed by Fasset,
1955, and nine by Rataj, 1975), but Haynes and Holm-Nielsen
(1994) accepted only two species, H. tenellum and H. bolivianum,
respectively. Jérémie et al. (2001), while describing a new species,
suggested a synonymization of these two. As well, Matias (2007)
considered H. tenellum and H. bolivianum as a single species.
Although morphologically extremely plastic and taxonomically
challenging genus, the limited available DNA evidence indicates
the presence of several species (Lehtonen and Myllys, 2008).
Bentham and Hooker (1883) described Helanthium as a section
under genus Alisma, but later Smith (1905) gave it a generic rank
(but misspelled the name as ‘Helianthium’). Since then, most
authors have considered Helanthium as a subgenus of Echinodorus
(e.g. Fasset, 1955; Rataj, 1975; Rogers, 1983; Haynes and HolmNielsen, 1994), until molecular studies confirmed that they are
separate (Soros and Les, 2002; Lehtonen and Myllys, 2008). The
close relationship between Helanthium and Ranalisma suggested
by Lehtonen and Myllys (2008) is not supported by the present
study, but Helanthium is resolved as the first divergent lineage
within n = 11 species, and Ranalisma as a sister to Sagittaria.
4.1.6. Caldesia Parl. pro parte
A genus with four generally accepted species, but in this
analysis C. oligococca was not resolved as a member of the
Caldesia-clade. Caldesia are palaeotropical-temperate, but a
fossilized Caldesia remains have been reported from the Miocene
deposits of North America (Smiley and Rember, 1985; Haggard
and Tiffney, 1997). Albidella leaves are morphologically indistinguishable from those of Caldesia, and therefore the leaf remains
(Smiley and Rember, 1985) cannot be identified with certainty.
However, the fruit fossils from the Early Miocene are typical
Caldesia fruits, confirming that Caldesia indeed was present in the
New World ca. 20 my ago (Haggard and Tiffney, 1997). The
polyphyletic origin of Caldesia suggested here should be tested
with molecular data.
4.1.7. Albidella Pichon + Caldesia Parl. pro parte
Haggard and Tiffney (1997) noticed the crested fruits of C.
oligococca to be highly different from other Caldesia, but their
striking similarity with Albidella nymphaeifolia (often treated as
Echinodorus) fruits remained unnoticed. Albidella has many other
morphological similarities with C. oligococca as well, but apparently only Hutchinson (1959) has ever treated A. nymphaeifolia as a
member of Caldesia. However, based on the current tree it would be
more appropriate to transfer C. oligococca to Albidella. This question
needs to be solved with molecular data. Three varieties are
recognized in C. oligococca, on the basis of fruit size and crestation
(den Hartog, 1957; Symoens, 1984). Further studies are required to
clarify whether these varieties would actually deserve to be raised
as full species, or just represent biogeographical variation or
ecologically driven plasticity.
4.1.8. Burnatia Micheli
A monospecific genus distributed in tropical Africa (Carter,
1960). The genus has never been included in any phylogenetic
analysis before, but is here resolved as the sister lineage of the
other small and mainly African genus, Wiesneria. These two genera
share highly reduced bisexual flowers.
4.1.9. Wiesneria Micheli
A small genus of three morphologically highly reduced species
from tropical Africa, Madagascar and India (Carter, 1960; Cook,
1990). Camenish and Cook (1996) considered Wiesneria as
phylogenetically isolated and old lineage within Alismataceae,
but molecular studies have often grouped it together with
Sagittaria (Les et al., 1997; Chen et al., 2004). The phylogenetic
analysis by Keener (2005) placed Wiesneria closer to Limnophyton
than Sagittaria, however, just like the morphological analysis
presented here. According to the morphological evidence the
closest relative of Wiesneria is Burnatia, a monospecific genus from
tropical Africa. Burnatia has never been sampled for any molecular
study, but it has reduced flowers as well, although the reduction is
not as extreme as in Wiesneria (Carter, 1960; Symoens, 1984).
Although a member of the clade with n = 11, Wiesneria appears to
be cytologically reduced as well, since n = 10 has been reported for
W. trianda (Mujawar et al., 2003). No other chromosome counts for
the genus are available.
4.1.10. Limnophyton Miq. + Astonia S.W.L.Jacobs
A paleotropical clade with four species (Aston, 1987). Limnophyton australiense, a species described by Aston (1987), was later
transferred to a new monospecific genus Astonia by Jacobs (1997).
The recognition of a separate genus was based on the differences in
bract and stamen coloration, fruit size, the lack of air chambers in
Astonia, and the flowering developmental sequence. In Astonia, the
peduncle bends toward the water surface after flowering, and the
pedicels of fruit producing flowers thicken and elongate until the
developing nutlets make contact with the water (Jacobs, 1997). The
upper part of the inflorescence, containing only male flowers,
grows upwards, thus producing a curved peduncle (Jacobs, 1997).
This developmental sequence has not been reported from other
species. However, the pedicels of fruit bearing flowers do thicken
in Limnophyton obtusifolium as well (Carter, 1960). Based on the
present morphological analysis Astonia is clearly nested within
well-supported Limnophyton, suggesting that Aston (1987) placed
the species correctly.
4.1.11. Echinodorus Rich. ex Engelm
A genus of ca. 28 species distributed in Western hemisphere,
mostly in the tropics but some species reaching temperate
climates (Lehtonen, 2008). As traditionally circumscribed (Fasset,
1955), Echinodorus was a polyphyletic assemblage of New World
Alismataceae, but monophyly of the genus was ascertained by
removing Albidella and Helanthium as separate genera (Lehtonen
and Myllys, 2008). Present analysis supports the monophyly of
strictly defined Echinodorus, but does not agree well with the
molecular evidence at the species-level resolution, except that E.
berteroi is resolved as the sister lineage of the rest of the genus.
4.1.12. Ranalisma Stapf
A genus of two species from tropical Africa and South East Asia
(Cook, 1990). Ranalisma is here recognized as the sister group of
Sagittaria, although the molecular studies have either grouped it
close to Helanthium (Lehtonen and Myllys, 2008), or resolved it as a
phylogenetically distinct lineage when Helanthium has not been
sampled (Les et al., 1997; Chen et al., 2004). The close relationship
with Helanthium was also strongly emphasized by den Hartog
(1957), although he included Helanthium in Echinodorus. It has also
S. Lehtonen / Aquatic Botany 91 (2009) 279–290
285
been anticipated that Ranalisma would be an intermediate genus
between Alismataceae and Limnocharitaceae (Charlton and
Ahmed, 1973), a suggestion somewhat supported by the rbcL
trees (Les et al., 1997; Chen et al., 2004). Morphologically,
Ranalisma fruits are basically indistinguishable from those of
Sagittaria (Haggard and Tiffney, 1997).
highly different views upon the classification (Rogers, 1983). Some
species groups recognized here are somewhat comparable with
the Keener (2005) Keener’s (2005) molecular phylogeny, but
overall the resolution within the genus is quite different. However,
neither morphological nor molecular (Keener, 2005) evidence
supports the often-recognized subgenera (e.g. Bogin, 1955).
4.1.13. Sagittaria L.
Apparently the most species rich genus in Alismataceae, with
ca. 40 species (Keener, 2005). The distribution is almost
cosmopolitan, but the main species diversity is concentrated in
North America (Keener, 2005). Sagittaria species are widely known
for their extreme morphological plasticity, which has caused
Acknowledgements
This study received financial support from the Kone Foundation. I thank Brian Keener and an anonymous referee for
contributing to improve this paper. The Willi Hennig Society is
acknowledged for making TNT publicly available.
Appendix A
Continuous characters coded as such
Number of parallel veins in blade
Number of peudowhorls in inflorescence
Bract length
Pedicel length
Flowers per pseudowhorl
Petal length
Stamen number
Achene length
Style length
Pollen pore number. Coded after Argue (1976) and Wang et al. (1997)
Traditionally coded characters
Life form: (0) perennial; (1) annual
Rhizome: (0) prolonged and decumbent: (1) short and erect
Corms: (0) absent; (1) present
Axillary stolons: (0) absent; (1) present
Roots: (0) not septate; (1) septate
Foliage: (0) submersed only; (1) amphibious; (2) emersed only
Leaf base: (0) attenuate-truncate; (1) cordate; (2) sagittate. This character was coded as additive
Veins pseudopinnate: (0) no; (1) yes
Waxy indument: (0) absent; (1) present
Indument: (0) glabrous; (1) pubescent
Petiole cross-section: (0) terete; (1) triangular
Petioles: (0) solid; (1) hollow
Petioles channeled: (0) no; (1) yes
Inflorescence: (0) erect; (1) creeping
Order of branching: (0) one; (1) two; (2) three. Branching order one refers to inflorescences lacking branches (umbels or racemes), two refers to inflorescences with
branches but lacking secondary branches, and three refers to inflorescences with branches which are branched again. This character was coded as additive
Flowers and branches: (0) not mixed in pseudowhorls; (1) mixed in pseudowhorls. In some species flowers and branches occur in the same pseudowhorls, but in other
species
pseudowhorls produce either branches or flowers. This character was coded as inapplicable for the species with branching order one (character 24)
Proliferations: (0) absent; (1) present. This character refers to the replacement of flower buds with vegetative buds in inflorescence
Inflorescence-stolons: (0) absent; (1) present. In some Alismataceae inflorescences can (especially in submersed conditions) be transformed into vegetative structures
with unlimited growth. These modified inflorescences have been called pseudostolons (Charlton, 1968), but are here referred as inflorescence-stolons, following
Mühlberg (2000) terminology. Typically inflorescence-stolons lack flowers, but in Luronium one to several flowers are often produced in each pseudowhorl together
with normal leaves (Cook, 1990)
Rachis: (0) non-alate; (1) alate
Bract apex: (0) obtuse; (1) acute-acuminate
Bracts per whorl: (0) three; (1) two
Bract connection: (0) free; (1) connected at the base; (2) fully connected. This character was coded as additive
Pedicel cross-section: (0) cylindric; (1) trigonous
Pedicels becoming expanded in fruits: (0) no; (1) yes
Pedicel orientation: (0) spreading; (1) reflexed
Pedicel length: (0) more or less equally long in all pseudowhorls; (1) shorter in lower pseudowhorls; (2) longer in lower pseudowhorls
Sexuality: (0) bisexual flowers only; (1) bisexual and unisexual flowers mixed; (2) unisexual flowers only; (3) dioecious inflorescences. This character was coded as
additive
Receptacle: (0) flattened; (1) conical
Sepal orientation: (0) erect and appressed to the receptacle; (1) spreading to reflexed. In the case of bisexual flowers this character is coded according to the pistillate
flowers.
Sepal length in relation to petals: (0) shorter than petals; (1) equalling petals; (2) longer than petals
Sepal midvein: (0) absent; (1) present
Cleistogamous flowers: (0) absent; (1) present
Petals: (0) present; (1) often absent in female flowers; (2) often absent in all flowers. This character was coded as additive
Petals basally: (0) clawed; (1) not clawed
Petals spotted at the base: (0) yes; (1) no
Petal colour: (0) creamy-yellow; (1) white; (2) purplish-pink
Petals distally: (0) entire; (1) erose; (2) retuse
Staminodia: (0) absent; (1) present. This character refers to the presence of non-functional stamens together functional ones in staminate or bisexual flowers
286
S. Lehtonen / Aquatic Botany 91 (2009) 279–290
Appendix A (Continued)
Filament pubescence: (0) glabrous; (1) minutely tomentose; (2) pubescent. This character was coded as additive
Filament shape: (0) filiform; (1) dilated
Anthers: (0) basifixed; (1) versatile
Anther shape: (0) oblong-ovate; (1) linear
Number of carpels: (0) 3-8; (1) less than 30; (2) 50-150; (3) hundreds. This character was coded as additive
Carpel connection: (0) free; (1) somewhat basally connate
Carpel arrangement: (0) in whorls; (1) spirally arranged; (2) bunched
Carpel opening: (0) open; (1) closed
Carpel size: (0) large; (1) small
Style position: (0) terminal; (1) ventral
Stigma: (0) expanded; (1) punctate
Achenes: (0) crowded; (1) loose aggregation
Fruit cross-section: (0) laterally flattened; (1) elliptical; (2) round
Fruit lateral shape: (0) obovate; (1) ovate; (2) conical; (3) reniformis
Fruit longitudinal ribs: (0) absent; (1) dorsally present; (2) dorsally and laterally present. This character was coded as additive
Longitudinal ribs: (0) smooth; (1) crested; (2) conspicuous spines
Fruit dorsal wings: (0) absent; (1) present
Dorsal wings: (0) entire; (1) dentate
Fruit lateral wings: (0) absent; (1) present
Fruit glands: (0) absent; (1) present
Endocarp: (0) thin and membranous; (1) thick and woody
Air chambers in fruits: (0) absent; (1) present
Ovule number: (0) one; (1) two; (2) numerous. This character was coded as additive
Ovule placentation: (0) laminar; (1) basal
Testa coat: (0) smooth; (1) sculptured
Ornamentation of testa: (0) multicostate; (1) papillose
Pollen surface: (0) granulate: (1) spinulate; (2) long-spinulate. This character was coded as additive
Pollen shape: (0) polyhedral; (1) spheroidal
Chromosome number: (0) 2n = 14; (1) 2n = 16; (2) 2n = 20; (3) 2n = 22; (4) 2n = 26; (5) 2n = 28; (6) 2n = 42. Following transformation costs were applied to chromosome
number changes: 0 > 1 1, 0 > 2 3, 0 > 3 4, 0 > 4 2, 0 > 5 1, 0 > 6 2, 1 > 0 1, 1 > 2 2, 1 > 3 3, 1 > 4 3, 1 > 5 2, 1 > 6 3, 2 > 0 3, 2 > 1 2, 2 > 3 1, 2 > 4 3, 2 > 5 4, 2 > 6 3, 3 > 0 4, 3 > 1 3,
3 > 2 1, 3 > 4 2, 3 > 5 3, 3 > 6 2, 4 > 0 2, 4 > 1 3, 4 > 2 3, 4 > 3 2, 4 > 5 1, 4 > 6 4, 5 > 0 1, 5 > 1 2, 5 > 2 4, 5 > 3 3, 5 > 4 1, 5 > 6 3, 6 > 0 2, 6 > 1 3, 6 > 2 3, 6 > 3 2, 6 > 4 4, 6 > 5 3
Appendix B. Data matrix, range coded characters.
Butomus umbellatus
Limnocharis flava
Limnocharis laforestii
Hydrocleys nymphoides
Hydrocleys mattogrosensis
Hydrocleys modesta
Hydrocleys martii
Hydrocleys parviflora
Butomopsis latifolia
Helanthium tenellum
Helanthium bolivianum
Helanthium zombiense
Ranalisma humile
Ranalisma rostrata
Albidella nymphaeifolia
Echinodorus berteroi
Echinodorus longipetalus
Echinodorus horizontalis
Echinodorus tunicatus
Echinodorus major
Echinodorus pubescens
Echinodorus palaefolius
Echinodorus subalatus
Echinodorus
Echinodorus
Echinodorus
Echinodorus
Echinodorus
Echinodorus
Echinodorus
Echinodorus
Echinodorus
Echinodorus
Echinodorus
Echinodorus
Echinodorus
Echinodorus
grisebachii
trialatus
scaber
emersus
macrophyllus
bracteatus
glaucus
cylindricus
paniculatus
reptilis
uruguayensis
cordifolius
floribundus
grandiflorus
Echinodorus longiscapus
Sagittaria montevidensis
ssp. montevidensis
0.000 0.000 1.398–1.544 1.699–2.041 1.114–1.699 1.954–2.176 0.778–0.954 1.602–1.699 1.602–1.602?
1.041–1.176 0.000 1.204–1.398 1.602–1.903 0.477–1.079 2.301–2.398 1.602–1.699 2.041–2.204? 0.477–0.845
0.699–0.954 0.000 1.041–1.322 1.176–1.699 0.000–0.845 1.954–2.176 1.000–1.176 1.954–2.079??
0.699–0.954 0.000 1.301–1.653 1.544–2.243 0.000–0.778 2.362–2.415 1.301–1.398 2.000–2.161 1.544–1.740?
0.699–0.845 0.000 1.477–1.602 1.301–1.699 0.301–0.699 1.954–2.079 0.602–0.778 1.954–1.954 1.000–1.176?
0.477–0.699 0.000 1.477–1.477 1.301–1.544 0.477–0.602 1.903–2.301 0.477–0.778 1.778–1.845 1.000–1.000?
0.699–0.845 0.000 1.301–1.653 1.544–2.243 0.000–0.778 2.362–2.398 1.079–1.255 2.000–2.176 1.544–1.740?
0.699–0.845 0.000 1.041–1.415 1.322–1.813 0.301–1.041 1.699–2.000 0.778–0.845 1.903–2.000 1.041–1.301?
0.477–0.845 0.000 1.114–1.176 1.301–2.146 0.477–1.176 1.778–1.778 0.903–0.954 1.954–2.079 1.301–1.477?
0.000–0.477 0.000–0.301 0.477–0.699 0.699–1.477 0.602–0.778 1.398–1.398 0.954–0.954 0.903–1.176 0.000–0.301 1.079–1.204
0.000–0.477 0.000–0.301 0.477–0.699 1.041–1.792 0.778–1.176 1.699–1.845 0.954–0.954 0.903–1.255 0.903–1.114 1.146–1.255
0.000–0.477 0.301–0.477 0.699–0.845 1.301–1.653 0.699–1.176 1.699–2.079 0.954–0.954 1.176–1.301 0.477–0.477 1.322–1.556
0.477–0.699 0.000 0.477–0.699 0.699–1.000 0.000–0.301 1.778–1.778 0.954–0.954 1.301–1.398 1.000–1.000 1.301–1.301
0.477–0.699 0.000 0.477–0.778 1.000–1.255 0.000–0.477 1.602–1.778 0.954–0.954 1.477–1.602 1.301–1.477 1.176–1.301
0.954–1.114 0.699–0.954 1.301–1.544 1.000–1.176 0.477–0.477 1.477–1.477 0.778–0.778 1.079–1.230 0.000–0.301 1.000–1.176
0.477–1.041 0.000–0.954 0.699–1.544 1.000–1.477 0.477–1.255 1.477–1.845 1.114–1.176 1.176–1.477 0.954–1.255 0.903–1.079
0.699–0.845 0.477–1.041 1.000–1.477 0.477–1.653 0.602–0.903 2.301–2.544 1.602–1.813 1.477–1.602 0.699–0.699 0.954–1.000
0.845–0.954 0.301–0.699 1.000–1.398 1.000–1.477 0.301–0.699 2.000–2.000 1.279–1.380 1.255–1.447 0.477–0.699?
0.845–1.114 0.000–0.778 1.477–1.778 1.301–1.602 0.845–1.699 2.000–2.000 1.279–1.380 1.415–1.633 0.602–1.000?
0.477–0.699 0.778–0.845 1.176–1.301 1.000–1.000 0.845–0.954 1.778–1.845 1.079–1.079 1.301–1.301 0.301–0.301 1.114–1.204
0.699–0.954 0.778–1.255 1.176–1.301 0.699–1.000 0.954–1.176 2.079–2.176 1.079–1.079 1.398–1.544 1.000–1.000?
0.845–1.041 0.903–1.255 1.176–1.544 0.000–1.176 0.845–1.398 2.079–2.079 1.079–1.079 1.255–1.398 0.602–1.000?
0.699–0.954 0.699–1.176 1.176–1.778 0.301–1.176 0.477–1.255 1.845–2.000 1.079–1.079 1.176–1.362 0.699–1.176 1.079–
1.204
0.477–0.845 0.477–1.079 0.477–1.398 0.301–1.000 0.477–0.954 1.699–1.699 0.954–1.079 1.176–1.342 0.301–0.699 0.954–1.041
0.477–0.845 0.602–1.176 1.000–1.398 0.301–0.845 0.477–0.845 1.903–1.903 1.079–1.079 1.176–1.301 0.699–0.699?
0.699–0.954 0.699–1.322 1.000–1.301 0.699–1.398 0.477–0.778 1.602–1.602 1.114–1.255 1.362–1.519 0.778–1.000?
0.954–1.114 0.903–1.322 0.778–1.000 0.699–1.000 0.477–1.079 2.146–2.204 1.146–1.342 1.301–1.477 0.477–1.000?
0.845–1.041 0.778–0.954 1.000–1.301 1.176–1.398 0.699–1.114 1.903–1.903 1.301–1.380 1.398–1.398 1.000–1.000 1.114–1.322
0.954–1.041 0.903–1.322 1.176–1.813 0.301–1.000 0.699–1.398 2.176–2.301 1.176–1.255 1.204–1.431 0.301–0.699?
0.845–1.114 0.778–1.146 0.778–1.255 1.000–1.255 0.778–1.230 2.342–2.398 1.380–1.477 1.342–1.477 0.699–0.699?
0.699–0.845 0.602–1.114 0.954–1.279 0.903–1.000 0.778–0.954 2.342–2.398 1.380–1.477 1.477–1.477 0.845–0.845?
0.699–0.845 0.602–1.041 1.000–1.740 1.000–1.602 0.699–1.322 2.301–2.398 1.279–1.342 1.176–1.477 0.000–0.903 1.041–1.204
0.477–0.477 0.000–0.477 0.903–0.903 1.544–1.778 0.477–0.699 2.079–2.176 1.176–1.342 1.176–1.176 0.477–0.477?
0.477–0.699 0.477–0.778 0.845–1.778 1.176–1.699 0.602–1.000 2.176–2.301 1.255–1.342 1.301–1.301 0.301–0.845?
0.699–0.954 0.477–0.903 1.000–1.699 1.477–1.875 0.778–1.342 2.079–2.176 1.176–1.447 1.114–1.477 0.301–1.000 1.079–1.176
1.041–1.322 0.903–1.204 1.000–1.602 1.000–1.602 0.845–1.255 2.255–2.342 1.380–1.477 1.255–1.447 0.301–0.477 1.079–1.176
0.845–1.114 0.699–1.114 1.176–1.653 1.176–1.813 0.845–1.279 2.301–2.342 1.322–1.544 1.301–1.477 0.301–0.699 1.146–
1.279
0.699–1.041 0.602–1.000 0.845–1.447 0.699–1.544 0.699–1.176 2.301–2.342 1.279–1.447 1.255–1.398 0.000–0.699 1.079–1.204
0.845–1.301 0.000–1.176 0.699–1.491 0.699–1.531 0.000–0.477 2.176–2.398 1.301–1.477 1.301–1.477 0.602–0.903 1.041–1.114
S. Lehtonen / Aquatic Botany 91 (2009) 279–290
287
Appendix B (Continued)
Sagittaria montevidensis
ssp. chilensis
Sagittaria intermedia
Sagittaria calycina ssp. calycina
Sagittaria calycina ssp. spongiosa
Sagittaria sprucei
Sagittaria rhombifolia
Sagittaria planitiana
Sagittaria guayanensis
ssp. guayanensis
Sagittaria guayanensis
ssp. lappula
Sagittaria tengtsungensis
Sagittaria pygmaea
Sagittaria potamogetifolia
Sagittaria trifolia
Sagittaria sagittifolia
Sagittaria natans
Sagittaria cuneata
Sagittaria longiloba
Sagittaria engelmanniana
Sagittaria australis
Sagittaria brevirostra
Sagittaria latifolia
Sagittaria secundifolia
Sagittaria fasciculata
Sagittaria weatherbiana
Sagittaria graminea
Sagittaria chapmanii
Sagittaria isoetiformis
Sagittaria lancifolia
ssp. lancifolia
Sagittaria lancifolia
ssp. media
Sagittaria ambigua
Sagittaria papillosa
Sagittaria cristata
Sagittaria macrocarpa
Sagittaria teres
Sagittaria rigida
Sagittaria sanfordii
Sagittaria macrophylla
Sagittaria demersa
Sagittaria platyphylla
Sagittaria subulata
Sagittaria filiformis
Sagittaria kurziana
Luronium natans
Burnatia enneandra
Baldellia ranunculoides
Baldellia repens
Baldellia alpestris
Caldesia parnassifolia
Caldesia reniformis
Caldesia oligococca var. oligococca
Caldesia oligococca var. echinata
Caldesia oligococca var.
acanthocarpa
Caldesia grandis
Astonia australiensis
Limnophyton obtusifolium
Limnophyton angolense
Limnophyton fluitans
Wiesneria trianda
Wiesneria filifolia
Wiesneria schweinfurthii
Damasonium californicum
Damasonium alisma
Damasonium polyspermum
Damasonium minus
Damasonium bourgaei
Alisma plantago–aquatica
Alisma triviale
Alisma lanceolatum
Alisma subcordatum
0.845–1.301 0.000–1.176 0.699–1.491 0.699–1.531 0.000–0.477 2.176–2.398 1.301–1.477 1.301–1.477 0.602–0.903 1.041–1.114
0.477–0.699 0.477–0.903 0.301–0.301 1.398–1.623 0.301–0.477 2.000–2.398 1.079–1.322 1.176–1.342 0.301–0.301?
0.845–1.301 0.477–1.079 0.477–1.301 0.699–1.398 0.000–0.477? 1.301–1.477 1.255–1.398 0.699–0.699?
0.845–1.301 0.301–0.602 0.301–0.699 0.699–1.301 0.000–0.477? 1.301–1.477 1.255–1.398 0.699–0.699?
1.041–1.041 0.477–1.079 0.602–0.778 0.000–1.176 0.301–0.477 1.699–1.903 0.954–1.079 1.602–1.778 0.699–0.699?
0.954–1.114 0.301–1.000 0.778–1.477 1.342–1.690 0.000–0.477 2.176–2.477 0.954–1.079 1.505–1.845 0.845–1.079?
0.954–1.079 0.301–0.477 0.699–1.079 0.699–1.176 0.000–0.477 1.699–2.079 0.778–0.778 1.176–1.342 0.000–0.301?
1.041–1.114 0.301–0.845 0.954–1.176 0.845–1.255 0.000–0.477 1.903–2.000 0.778–0.954 1.230–1.342 0.301–0.699 1.114–1.204
1.041–1.114 0.301–0.845 0.954–1.176 0.845–1.255 0.000–0.477 1.903–2.000 0.778–1.000 1.477–1.602 0.699–0.954 1.114–1.204
0.000–0.477 0.477–0.845 0.477–0.699 1.301–1.778 0.301–0.477 2.000–2.000 1.176–1.380 1.477–1.602 1.000–1.000 1.079–1.079
0.000 0.301–0.477 0.477–0.699 1.176–1.602 0.301–0.602 1.845–1.954 0.954–1.176 1.176–1.301 1.000–1.079 1.079–1.146
0.000–0.477 0.301–0.699 0.301–0.699 1.079–1.602 0.301–0.477 1.602–2.000 0.954–1.322 1.398–1.477 1.000–1.000?
0.477–1.041 0.699–1.146 0.602–1.255 1.000–1.255 0.301–0.477? 1.301–1.380 1.477–1.602 1.000?
0.477–1.041 0.301–1.000 0.477–1.176 0.699–1.176 0.301–0.477 2.000–2.176 1.301–1.380 1.398–1.653 0.301–0.903 1.041–1.301
0.000–0.477 0.301–0.778 0.477–1.176 1.000–1.301 0.477–0.477 1.903–2.000 1.301–1.380 1.477–1.602 0.301–0.903?
0.699–1.176 0.301–1.000 0.845–1.602 0.699–1.301 0.301–0.477 1.903–2.079 1.176–1.380 1.255–1.415 0.000–0.602 1.041–1.176
0.778–0.778 0.699–1.230 0.778–1.176 1.301–1.398 0.301–0.477 1.778–2.176 1.079–1.204 1.079–1.398 0.000–0.778?
? 0.301–0.602 0.699–1.398 1.176–1.544 0.301–0.477 1.903–2.079 1.176–1.398 1.380–1.602 1.000–1.322?
? 0.699–1.079 0.845–1.477 0.477–1.362 0.301–0.477 1.903–2.079 1.176–1.398 1.322–1.505 0.602–1.230?
? 0.699–1.079 1.000–1.602 1.000–1.398 0.301–0.477 1.903–2.079 1.176–1.398 1.322–1.491 0.602–1.230?
0.845–1.114 0.477–0.954 0.477–0.903 0.903–1.398 0.301–0.477 1.954–2.255 1.204–1.255 1.398–1.544 1.000–1.301 1.000–1.146
0.000 0.301–0.699 0.000–0.301 0.778–1.398 0.301–0.477 1.903–2.079? 1.398–1.477 0.699–0.699?
0.000 0.301–0.699 0.301–0.699 1.176–1.653 0.301–0.477 1.477–1.699? 1.398–1.477 0.699–0.699?
0.000–0.477 0.301–0.903 0.477–1.079 1.845 0.301–0.477? 1.079–1.255 1.255–1.342 0.477–0.477?
0.000–0.477 0.301–0.903 0.301–1.176 0.699–1.204 0.301–0.477 1.778–1.903 1.079–1.255 1.176–1.447 0.301–0.301 1.041–1.342
0.000–0.477 0.477–1.079 0.301–1.176 1.301 0.301–0.477? 1.255–1.380 1.079–1.322 0.000?
0.000 0.301–0.602 0.301–0.477 1.000–1.544 0.301–0.477 1.778–1.903 1.079–1.176 1.342–1.447 0.301–0.301?
0.845–0.954 0.602–1.114 0.477–0.778 1.279–1.398 0.301–0.477 1.903–2.176 1.301–1.447 1.204–1.398 0.477–0.845 1.000–1.230
0.845–0.954 0.602–1.114 0.477–0.778 1.279–1.398 0.301–0.477 1.903–2.176 1.301–1.447 1.204–1.398 0.477–0.845 1.000–1.230
0.000 0.477–1.079 1.000–1.477 1.176–1.544 0.301–0.477 1.778–1.903 1.176–1.322 1.398–1.477 0.301–0.301?
0.000 0.602–1.079 0.602–0.903 1.000–1.653 0.301–0.477 1.903–2.079 1.176–1.322 1.079–1.176 0.000–0.477 1.079–1.176
0.000 0.477–0.778 0.602–1.000 1.176–1.477 0.301–0.477 1.778–1.903 1.079–1.255 1.398–1.477 0.602–0.845 1.041–1.204
0.000–0.477 0.477–0.699 0.301–0.477 1.398 0.301–0.477? 1.079–1.255 1.301–1.477 0.699–0.699?
0.000 0.301–0.602 0.301–0.477 1.000–1.477 0.301–0.477 1.778–1.903 1.079–1.176 1.301–1.477 0.477–0.602?
0.000–0.954 0.301–0.903 0.477–0.778 1.000–1.477 0.301–0.477 1.778–1.903 1.176–1.380 1.301–1.477 0.903–1.146 1.000–1.342
0.477–0.954 0.477–1.000 0.699–0.903 0.699–1.398 0.301–0.477 1.778–1.903 1.176–1.380 1.301–1.477 0.301–0.778?
0.477–0.602 0.477–0.699 0.845–1.041 0.778–1.505 0.477–0.477 2.176–2.176 1.079–1.204 1.491–1.544 0.778–1.079 1.114–1.204
0.954–1.041 0.301–0.845 0.301–0.602 1.000–1.301 0.477–0.477 1.903–2.079 1.079–1.176 1.176–1.176 1.041–1.041?
0.000–0.845 0.477–0.903 0.477–0.778 0.699–1.301 0.301–0.477 1.903–1.954 1.176–1.322 1.079–1.301 0.477–0.778?
0.699–0.954 0.301–0.602 1.176–1.602 0.301–1.398 0.000–0.477 1.301–1.778 0.778–0.778 1.301–1.301 0.301–0.602 1.114–1.279
0.000 0.301–1.000 0.477–1.000 1.176–1.653 0.301–0.477 1.778–1.903 0.954–1.079 1.699–1.699 0.000–0.477?
0.000 0.699–1.301 0.477–1.398 1.176–1.653 0.301–0.477 1.778–1.903 0.954–1.176 1.699–1.699 0.301–0.903?
0.000–0.477?? 1.477–1.845 0.000–0.699 1.602–2.000 0.778–0.778 1.000–1.301 0.000 1.279–1.362
0.699–0.845 0.000–0.699 1.000–1.398 0.477–1.000 0.477–0.477 1.000–1.477 0.954–0.954 1.176–1.398 0.000 1.301–1.322
0.000–0.477 0.000–0.301 0.699–0.699 1.301–1.778 0.778–1.176 1.602–1.903 0.778–0.778 1.301–1.544? 1.342–1.398
0.000–0.477 0.301–0.477? 1.301–1.778 0.000–0.778 1.699–2.079 0.778–0.778 1.255–1.301??
0.000–0.477 0.000??? 1.477–1.602 0.778–0.778???
0.699–1.041 0.477–0.778 1.000–1.000 1.176–1.602 0.477–0.477 1.544–1.653 0.778–0.778 1.477–1.602 1.000–1.176 1.000–1.079
1.114–1.230 0.602–0.903 1.000–1.000 1.000–1.602 0.477–0.477 1.602–1.699 0.778–0.778 1.477–1.477 1.000–1.176?
0.954–1.230 0.699–1.079 1.176–1.778 1.000–1.544 0.477–0.477 1.477–1.778 0.778–0.778 1.477–1.778 0.000 0.301–0.301
0.954–1.230 0.699–1.079 1.699–2.061 1.000–1.544 0.477–0.477 1.398–1.398 0.778–0.778 1.176–1.477 0.000?
0.954–1.230 0.699–1.079 1.398–1.544 1.000–1.544 0.477–0.477 1.602–1.778 0.778–0.778 1.699–1.903 0.000?
0.954–1.041 0.477–0.778 1.301–1.301 1.301–1.398 0.477–0.477 1.778–1.903 0.954–1.079 1.176–1.176 1.176–1.176 1.255–
1.255
1.041–1.301 0.477–0.903 1.477–1.477 0.954–1.146 1.000–1.362 1.778–1.799 0.778–0.778 2.000–2.114 0.778–0.778?
1.230–1.279 0.699–0.845 1.000–1.301 1.301–1.653 0.477–1.000 1.778–1.954 0.778–0.778 1.602–1.699? 1.146–1.255
1.230–1.398 0.602–0.778 1.301–1.477 0.954–1.146 0.778–1.176 1.778–1.954 0.778–0.778 1.903–1.903 0.699–0.699 1.255–
1.255
0.477–0.477 0.301–0.602 1.000–1.301 1.000–1.000 0.477–1.079 1.845–1.845 0.778–0.778 1.602–1.699 1.000–1.000?
0.000–0.477 0.699–0.903 0.301–0.477 0.000 0.477–0.903 1.176 0.477–0.477 1.477–1.602 0.699–1.000 1.301–1.342
0.000 0.699–1.000 0.301–0.477 0.000–0.301 0.477–0.903 1.176 0.477–0.477 1.301–1.477 1.000–1.176?
0.000–0.477 0.699–1.079 0.301–0.477 0.000–0.301 0.477–0.903 1.176 0.477–0.477 1.477–1.602 1.301–1.301 1.255–1.255
0.477–0.699 0.000–0.954 1.000–1.176 1.301–1.778 0.602–1.000 1.778–2.000 0.778–0.778 1.477–1.740 1.477–1.778 1.255–1.301
0.477–0.699 0.000–0.602 0.699–0.699 1.176–1.477 0.699–1.114 1.580–1.672 0.778–0.778 1.477–1.778 1.301–1.699 1.279–
1.322
0.477–0.699 0.000–0.301? 1.176–1.477 0.602–0.903 1.699–1.763 0.778–0.778?? 1.477–1.477
0.477–0.699 0.301–0.602? 1.176–1.477 0.602–0.903 1.301–1.477 0.778–0.778 1.699–1.778? 1.398–1.519
0.477–0.699 0.000–0.699? 1.176–1.477 0.602–1.000 1.491–1.591 0.778–0.778?? 1.255–1.301
0.699–0.954 0.602–0.954 1.146–1.477 1.000–1.556 0.602–1.000 1.531–1.806 0.778–0.778 1.230–1.491 0.778–1.176 1.255–1.342
0.699–0.954 0.602–0.954 1.602–1.954 1.079–1.556? 1.580–1.653 0.778–0.778 1.255–1.477 0.602–0.778 1.398–1.505
0.699–0.845 0.477–0.778 0.845–1.230 1.079–1.505 0.477–0.778 1.643–1.813 0.778–0.778 1.301–1.462 0.602–0.778 1.255–1.505
0.699–0.845 0.477–1.000 0.778–1.176 0.845–1.301? 1.255–1.398 0.778–0.778 1.176–1.398 0.301–0.602 1.322–1.415
288
S. Lehtonen / Aquatic Botany 91 (2009) 279–290
Appendix B (Continued)
Alisma gramineum
Alisma wahlenbergii
Alisma orientale
Alisma canaliculatum
Alisma rariflorum
0.000–0.699 0.477–0.699 0.699–1.114 1.000–1.477 0.477–0.954 1.342–1.568 0.778–0.778 1.255–1.415 0.602–0.699 1.301–1.398
0.000–0.477 0.000–0.301 0.301–0.699 0.778–1.342 0.477–0.778 1.204–1.462 0.778–0.778 1.204–1.380 0.477–0.602?
0.699–0.954 0.602–0.954 1.146–1.342 0.903–1.342 0.477–0.954 1.398–1.519 0.778–0.778 1.114–1.322 0.602–0.699 1.279–
1.322
0.477–0.699 0.477–0.778 0.845–1.176 0.778–1.380 0.477–0.954 1.398–1.591 0.778–0.778 1.301–1.477 0.699–0.903 1.380–1.462
0.477–0.699 0.477–0.778 0.845–1.000 1.342–1.544 0.301–0.477 1.699–1.845 0.778–0.778 1.301–1.519 1.041–1.176 1.255–
1.342
Appendix C. Data matrix, traditionally coded characters? = missing data, = inapplicable data. Polymorphic characters are scored as
follows: a = [01], b = [12]
Butomus umbellatus
Limnocharis flava
Limnocharis laforestii
Hydrocleys nymphoides
Hydrocleys mattogrosensis
Hydrocleys modesta
Hydrocleys martii
Hydrocleys parviflora
Butomopsis latifolia
Helanthium tenellum
Helanthium bolivianum
Helanthium zombiense
Ranalisma humile
Ranalisma rostrata
Albidella nymphaeifolia
Echinodorus berteroi
Echinodorus longipetalus
Echinodorus horizontalis
Echinodorus tunicatus
Echinodorus major
Echinodorus pubescens
Echinodorus palaefolius
Echinodorus subalatus
Echinodorus grisebachii
Echinodorus trialatus
Echinodorus scaber
Echinodorus emersus
Echinodorus macrophyllus
Echinodorus bracteatus
Echinodorus glaucus
Echinodorus cylindricus
Echinodorus paniculatus
Echinodorus reptilis
Echinodorus uruguayensis
Echinodorus cordifolius
Echinodorus floribundus
Echinodorus grandiflorus
Echinodorus longiscapus
Sagittaria montevidensis ssp. montevidensis
Sagittaria montevidensis ssp. chilensis
Sagittaria intermedia
Sagittaria calycina ssp. calycina
Sagittaria calycina ssp. spongiosa
Sagittaria sprucei
Sagittaria rhombifolia
Sagittaria planitiana
Sagittaria guayanensis ssp. guayanensis
Sagittaria guayanensis ssp. lappula
Sagittaria tengtsungensis
Sagittaria pygmaea
Sagittaria potamogetifolia
Sagittaria trifolia
Sagittaria sagittifolia
Sagittaria natans
Sagittaria cuneata
Sagittaria longiloba
Sagittaria engelmanniana
Sagittaria australis
Sagittaria brevirostra
Sagittaria latifolia
Sagittaria secundifolia
Sagittaria fasciculata
Sagittaria weatherbiana
Sagittaria graminea
Sagittaria chapmanii
10000100001000000001000000000100000200010101000001200–0–0000200–??
11000100001001001001001110000000000001010011000010010–0–000020101?
11000100001001001001001110000000000001010011000010010–0–00002010??
10000110000101001000000000000000000a01010101000000210–0–000020111?
10000110000101001000000000000200001001010101000000210–0–00002011??
10000100000101001001000000000000001000010101000000210–0–00002011??
10000110000101001000000000000010001001010101000000210–0–00002011??
1100010000010100000100000000021000100a010101000000210–0–00002011??
0100010000100a000001000000000100011100000101000000210–0–000020111?
1100010000000a00110101000000000000112000001021111111200–0000010–11
1100010000000a00110101000000000000112000001021111111200–0000010–11
1100010000000a00110101000000000000112000001021111111200–0000010–11
1100010000100a001101110000011000001b00000010111010000–100100010–11
110001a000010a001101110000011000001100000010111010000–100100010–11
110001100000002000010000000010000??10000001021111103210–0000010–11
010001a000100021000100000001100000110000102011101020200–0100010–11
1000020100100000100100001001000001110000113011101000200–0000010–11
1000021000000100100100001001000001110000103011101020200–0100010–??
1000021000000000100100001001000001110000103011101020200–0100010–??
1000010100100000100100000001100001010000112011101020200–0100010–11
1000020001000011000100000001100001010000112011101020200–0100010–??
100001a001101011101100000001100001010000112011101020200–0100010–??
1000010001101011101100000001100001010000112011101020200–0100010–11
1000010100100a11100100001001100001110000112011101020200–0100010–11
1000010100100000101100001001100001110000112011101020200–0000010–??
1000021001000011100100000001100001110000112011101020200–0100010–??
1000021001000011100100000001100001110000112011101020200–0000010–??
1000021001000011100100000001100001110000112011101020200–0000010–11
1000021001000011101100001001100001110000112011101020200–0100010–??
1000021010000000000100000001100001110000112011101020200–0100010–??
1000020010000000000100000001100001110000112011101020200–0100010–??
1000010000100011100100000001100001110000112011101020200–0000010–11
1000020000000100100100000001100001110000112011101020200–0100010–??
1000010100000a00100100000001100001110000112011101020200–0100010–??
100002a001000111100100000001100001110000112011101020200–0100010–11
1000021001000011100100000001100001110000112011101020200–0100010–11
100002a001000011100100000001100001110000112011101020200–0100010–11
100002a001000011100100000001100001110000112011101020200–0100010–11
1000112000000a110001010110110000000100000030111010000–100a00010–21
1000112000000a0–0001010110110000000100100030111010000–100a00010–??
10001220001000110001010110110000001100110030111010000–100a00010–??
aa00112000?00a0–0001010110110000001100100030111010000–100a00010–??
0100112000?00a0–0001010110110000001100000030111010000–100a00010–??
10001220001000110001010111110000001100000030111010000–100a00010–??
100011000010000–0001010111110000000100000030111010000–100000010–??
110012000a10000–0001000111110000001100000030111010000–100000010–??
111011200a10010–0001010110110000000100000030111010000–110000010–21
111011200a10010–0001010110110000000100000030111010000–110000010–??
111011000000000–0001010101210000001100010030111010000–100100010–21
1110110000?0000–0001000–01210000001100010030111010000–110000010–21
1111112000?0000–0001010101210000001100010030111010000–100a00010–??
1111122000?000110001010000211000001100000030111010000–100100010–??
11111120001000110001010001111000000100000130111010000–100a00010–21
1000102000000a0–0001010001111000001100000030111010000–100a00010–??
11111120001000110001010000211000001100000030111010000–100100010–21
10111220000000110001010000211000001100000130111010000–100a00010–??
11111120001000110001010000211000001100000030111010000–101100010–??
111112200010000–0001010001211000001100000030111010000–101000010–??
11111220000000110001010000211000001100000030111010000–101000010–??
111111200a1000110001010000211000001100000030111010000–100a00010–21
100010000000000–0001010000211000001100110030111010000–111100010–??
100111000000000–0001010000211000001100110030111010000–101a00010–??
1111110000?000110001010002211000001100210030111010000–101100010–??
1aa011000010000–0001010002211000001100210030111010000–101100010–21
1001110000?000100001010000211000001100210030111010000–101100010–??
S. Lehtonen / Aquatic Botany 91 (2009) 279–290
289
Appendix C (Continued)
Sagittaria isoetiformis
Sagittaria lancifolia ssp. lancifolia
Sagittaria lancifolia ssp. media
Sagittaria ambigua
Sagittaria papillosa
Sagittaria cristata
Sagittaria macrocarpa
Sagittaria teres
Sagittaria rigida
Sagittaria sanfordii
Sagittaria macrophylla
Sagittaria demersa
Sagittaria platyphylla
Sagittaria subulata
Sagittaria filiformis
Sagittaria kurziana
Luronium natans
Burnatia enneandra
Baldellia ranunculoides
Baldellia repens
Baldellia alpestris
Caldesia parnassifolia
Caldesia reniformis
Caldesia oligococca var. oligococca
Caldesia oligococca var. echinata
Caldesia oligococca var. acanthocarpa
Caldesia grandis
Astonia australiensis
Limnophyton obtusifolium
Limnophyton angolense
Limnophyton fluitans
Wiesneria trianda
Wiesneria filifolia
Wiesneria schweinfurthii
Damasonium californicum
Damasonium alisma
Damasonium polyspermum
Damasonium minus
Damasonium bourgaei
Alisma plantago–aquatica
Alisma triviale
Alisma lanceolatum
Alisma subcordatum
Alisma gramineum
Alisma wahlenbergii
Alisma orientale
Alisma canaliculatum
Alisma rariflorum
111111000000000–0001010000211000001100110030111010000–101100010–??
10001200001000110001010000211000001100200030111010000–100100010–21
10001200001000110001010000211000001100200030111010000–100100010–??
11111200001000110001000000211000001100000030111010000–101a00010–??
10001200001000110001010000211000001100000030111010000–101a00010–21
a11110000010000–0001010000211000001100210030111010000–101100010–21
a111100000?0000–0001010000211000001100210030111010000–101100010–??
111110000000000–0001010000211000001100210030111010000–0–1100010–??
111111200010000–0001010111211000001100210030111010000–100a00010–21
111111000010000–0001010112211000001100210030111010000–0–0000010–??
111112200010000–0001010112211000001100000030111010000–100a00010–21
111110000000000–0001010112211000001100010030111010000–0–0000010–??
111111a00010000–0001010112211000001100210030111010000–0–1000010–??
111110000000000–0001010111211000001100010030111010000–101a00010–21
11111120000001100001010002210000001100010030111010000–101100010–??
11111000000001100001010112211000001100010030111010000–0–1100010–??
110001a000000111110100000000?001010110000010011001212–0–0000010–01
1100010000000010000100000030120011110001001021111100201001?0010–11
1100010000000a00100100000000100100011000001021101101100–0000010–00
1100010000000100110100000000100000021000001021101101100–0000010–0?
1100010000000a001101000000001001000a1001011021101101100–0000010–??
1100011000000011100100000000000000110000001021101120200–001a010–01
1100011000000011100100000000010000110000001021101120200–001a010–??
1100011000000020000101000000100000110001101021111113210–0000010–00
1100011000000020000101000000100000110001101021111113210–0000010–??
1100011000000020000101000000100000110001101021111113220–0000010–??
1100011000000010100100000000000000110000001021101120200–0010010–01
1100012000000000000100011210100000100011001021110110120–0010010–??
1100012001100011000100011010100000110001001021110120100–0011010–11
1100012001000011000100001010100000110001001021110120100–0011010–11
1000010101000011000100000010100000110001001021110120100–0011010–??
01000100000001001001020–020120021100001000001101121200–0011010–21
11000100000001001001020–2201200211?0001000001101121000–0011010–??
01000100000001001001020–0201200201b0001000001101121200–0011010–21
11000200000000110001000000001000000b1001111101101002200–0000010–00
1100020000000011000100000000100000011000001101101002200–0000110–00
01000200000000000001000000001000000b1000001101101002200–0000200–01
010002a0000000110001000000001000001b1000001101101002200–0000110–00
01000200000000110001000000001000000b1000001101101002200–0000110–00
11000100000000210001000000000000000b1001001000110001100–0000010–00
1100020000000021000100000000000000111001001000110001100–0000010–00
11000200000000210001000000000000000210010010001100001–0–0000010–00
110002a0000000210001000000000000000110010010001100001–0–0000010–00
11000100000000110001000000000001001210010010001100001–0–0000010–00
11000100000000110001000000000001000200010010001100001–0–0000010–??
110002a0000000210001000000000000000210010010001100001–0–0000010–00
11000200000000210001000000000000000100010010001100001–0–0000010–00
11000200000000110001000000000000000110010010001100001–0–0000010–00
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