Alloteropsis semialata(R.Br.) Hitchcock. Contr.
U. S. Nat. Herb. 12: 210 (1909).
Classification. (GPWG 2001) : Subfamily
Panicoideae. Paniceae.
Common name:
Cockatoo Grass.
Basionym and/or
Replacement Name: Panicum
semialatum R.Br., Prodromus Florae Novae Hollandiae 1: 192. 1810.
Type of Basionym or
Protologue Information: Australia:, R. Brown 6101 (HT: BM; IT: K,
US-75473 (fragm.)) Littora Novae Hollandiae intra tropicum.
Recent synonyms:
Axonopus semialatus (R.Br.) Hook., Alloteropsis eckloniana (Nees)
Hitchc.
Key references
(books and floras): [1810]. R.Brown, Prodromus (192 as Panicum
semialatum), [1878] G.Bentham, Flora Australiensis 7 (472 as Panicum
semialatum, 545 as Arundinella schultzii), [1952] C.A.Gardner, Flora
of Western Australia 1 Gramineae (231), [1969] E.E.Henty, Manual
Grasses New Guinea (25), [2002] D.Sharp & B.K.Simon, AusGrass,
Grasses of Australia, [2008] S.W.L.Jacobs, R.D.B.Walley &
D.J.B.Wheeler, Grasses of New South Wales (114).
Illustrations:
[1952] C.A.Gardner, Flora of Western Australia 1 Gramineae (229,
Pl. 68), [1983] J.C.Tothill & J.B.Hacker, Grasses of Southern Queensland
(88), [1984] N.T.Burbidge. rev. S.W.L.Jacobs, Australian Grasses (45), [2008] S.W.L.Jacobs, R.D.B.Whalley &
D.J.B.Wheeler, Grasses of New South Wales, 4th edn (114).
Derivation: L. semi,
half; ala, wing; -ata, possessing; Upper glumes winged.
Habit.
Perennial. Rhizomes present, short. Culms erect or geniculately ascending,
20–150 cm tall. Mid-culm internodes glabrous. Mid-culm nodes bearded. Lateral
branches simple. Leaves basal and cauline. Leaf-sheaths glabrous on surface or
hairy. Ligule a fringed membrane (ca 0.75mm) or a fringe of hairs, a ciliate
membrane (ca 0.75mm), 0.4–0.6 mm long. Leaf-blades filiform, flat or convolute,
10–50 cm long, 1–10 mm wide. Leaf-blade surface scabrous, glabrous or
indumented.
Inflorescence.
Inflorescence digitate, with racemose branches. Racemes 2–4(–8), 2–22 cm long.
Spikelets.
Spikelets pedicelled, 2–4 in the cluster. Fertile spikelets 2-flowered, the
lower floret barren (rarely male), the upper fertile, comprising 1 basal
sterile florets, comprising 1 fertile floret(s), without rachilla extension or
with a barren rachilla extension, ovate, dorsally compressed, 4–7.5 mm long.
Glumes. Glumes
dissimilar, thinner than fertile lemma. Lower glume ovate, membranous, without
keels, 3 -nerved. Lower glume apex mucronate or awned. Upper glume ovate, 4.5–7
mm long, membranous, without keels, 5 -nerved. Upper glume surface indumented.
Upper glume apex mucronate or awned. Florets. Basal sterile florets 1,
male, with palea. Lemma of lower sterile floret 100 % of length of spikelet,
chartaceous, 5 -nerved.
Fertile lemma 3.5–7 mm
long, without keel, 5 -nerved. Lemma apex awned, 1 -awned. Median (principal)
awn 1.5–3 mm long overall. Lodicules present. Anthers 2 or 3. Grain 1.3–1.5 mm
long.
Continental
Distribution: Africa, Temperate Asia, Tropical Asia, Australasia, and
Pacific.
Australian
Distribution: Western Australia, Northern Territory, Queensland, New South
Wales.
Western Australia:
Gardner, Fitzgerald, Hall. Northern Territory: Darwin & Gulf,
Victoria River. Queensland: Burke, Burnett, Cook, Darling Downs,
Leichhardt, Maranoa, Moreton, North Kennedy, Port Curtis, South Kennedy,
Warrego, Wide Bay. New South Wales: North Coast, Northern Tablelands,
North-Western Slopes.
Notes.
Extremely variable in the size and shape of the inflorescence and vegetative
parts. On some specimens the area from the last lateral nerve and the margin
reflexes outward and produces a distinctly winged spikelet. Ellis (1974) found
both the Kranz and non-Kranz leaf anatomy in this species and discussed the
significance of this unique situation. Gibbs Russell (1983), working with
African material, correlated certain leaf characteristics with leaf anatomy and
recognized a subspecies, A. semialata subsp. eckloniana (Nees),
Gibbs Russell) for the C3 specimens. This treatment could not be applied to
Australian specimens.
In tropical and
subtropical rain forests, Brigalow forests, tropical and subtropical sub-humid
woodlands, arid and semi-arid low woodlands, and coastal grasslands. Common
throughout the tropics and subtropics of Australia. Flowers sporadically
throughout the year but mostly Dec.-May.
