Oplismenus compositus

Oplismenus compositus (L.) P.Beauv.
Ess. Agrost.
54, 168 (1812).

Classification. (GPWG 2001) : Subfamily Panicoideae. Paniceae.

Basionym and/or
Replacement Name:
L., Sp. Pl. 1: 57 (1753).

Type of Basionym or
Protologue Information
: LT: Herb. Hermann 42, v. 3, fol. 45,
(BM-SL). LT designated by Hitchcock, U.S.D.A. Bull. 772: 238 (1920);
also Davey & Clayton, Kew Bull. 33: ? (1978).

Key references
(books and floras):
[1810]. R.Brown, Prodromus (194 as Orthopogon),
[1878] G.Bentham, Flora Australiensis 7 (491), [1969] E.E.Henty, Manual
New Guinea (132), [2002] D.Sharp & B.K.Simon, AusGrass,
Grasses of Australia

Perennial. Culms prostrate, 15–150 cm tall. Mid-culm nodes glabrous or
pubescent. Ligule a fringed membrane, a ciliate membrane, 0.8–1.5 mm long.
Leaf-blades lanceolate or ovate, 2–24 cm long, 8–27 mm wide. Leaf-blade surface

Inflorescence compound, a panicle of racemes. Racemes 4–12, 2.5–11 cm long
(lowest). Central inflorescence axis 5–25 cm long.

Spikelets. Spikelets
sessile and pedicelled, 2 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,
lanceolate, laterally compressed, 2.5–4 mm long.

Glumes similar or dissimilar, thinner than fertile lemma. Lower glume ovate,
herbaceous, keeled, 1-keeled, 3–5 -nerved. Lower glume surface glabrous or
indumented. Lower glume apex awned. Upper glume ovate, 1.6–3 mm long,
herbaceous, keeled, 1-keeled, 5–7 -nerved. Upper glume surface glabrous or
indumented. Upper glume apex muticous or awned. Florets. Basal sterile
florets 1, male or barren, with palea or without significant palea. Lemma of
lower sterile floret 100 % of length of spikelet, membranous, 1-keeled, 7–11
-nerved, mucronate or awned.

Fertile lemma 2–3.3 mm
long, without keel, 7 -nerved. Palea without keels.

: Africa, Temperate Asia, Tropical Asia, Australasia, Pacific,
North America, and South America.

: Northern Territory, Queensland, Christmas Is.

Northern Territory:
Darwin & Gulf. Queensland: Cook, North Kennedy, South Kennedy, Port

Diagnostic features include the elongate lowermost primary branches with
distant spikelet pairs. Oplismenus compositus intergrades with O.
and identification of some specimens is difficult.

Distributed throughout
the tropics. In tropical heaths, tropical and subtropical rain forests,
tropical and subtropical wet sclerophyll forests, tropical and subtropical
sub-humid woodlands, and coastal grasslands. In Australia, it is restricted to
the coastal plains of tropical Qld. Flowers Apr.-Aug.


AVH 2011


Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith