Cenchrus arnhemicus (Hitchcock) Morrone, Ann. Bot. 106:127 (2010)
Classification. (GPWG 2001) : Subfamily Panicoideae. Paniceae.
Type of Basionym or Protologue Information: HT: W.V. Fitzgerald 600, May 1905, Australia: Western Australia: collected at Devil's Pass, Napier Range, Kimberley Division, May 1905 (US-1172752).
Recent synonyms: Pennisetum arnhemicum, Pseudochaetochloa australiensis
Key references (books and floras): [1878] G.Bentham, Flora Australiensis 7 (496 as Pennisetum arnhemicum), [1952] C.A.Gardner, Flora of Western Australia 1 Gramineae (270), [2002], as Pseudochaetochloa australiensis; D.Sharp & B.K.Simon, AusGrass, Grasses of Australia, as Pseudochaetochloa australiensis.
Illustrations: [1952] C.A.Gardner, Flora of Western Australia 1 Gramineae (269, Pl. 77). as Pseudochaetochloa australiensis.
Habit. Perennial. Rhizomes present, short. Culms erect, 50–120 cm tall, 3–12 -noded. Mid-culm nodes pubescent. Ligule a fringe of hairs, 0.7–2.3 mm long. Leaf-blades flat or conduplicate or involute, 20–50 cm long, 1–5.5 mm wide. Leaf-blade surface scabrous.
Inflorescence. Inflorescence solid, a panicle. Panicle linear, 7–20 cm long.
Spikelets. Spikelets sessile, 1 in the cluster. Male spikelets pedicelled. Involucre composed of bristles. 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, dorsally compressed, 4–6 mm long.
Glumes. Glumes similar, thinner than fertile lemma. Lower glume ovate, membranous, without keels, 0–3 -nerved. Lower glume apex muticous or mucronate. Upper glume lanceolate or ovate, 2.3–2.6 mm long, membranous, without keels, 3(–5) -nerved. Florets. Basal sterile florets 1, barren, without significant palea. Lemma of lower sterile floret 100 % of length of spikelet, membranous, 5 -nerved, muticous or mucronate. Fertile florets female.
Fertile lemma 3.4–3.8 mm long, without keel.
Continental Distribution: Australasia.
Australian Distribution: Western Australia, Northern Territory.
Western Australia: Gardner, Fitzgerald, Hall. Canning. Northern Territory: Victoria River.
Notes. Widespread in the Kimberley region of W.A. and the N.T. In tropical and subtropical sub-humid woodlands, semi-arid shrub woodlands, and arid hummock grasslands. A distinctive endemic. Flowers Mar.-Aug.
