Mnesithea rottboellioides (R. Br.) R. de Koning & M.S.M. Sosef. Blumea 31: 291(1986).
Classification. (GPWG 2001) : Subfamily Panicoideae. Andropogoneae.
Basionym and/or Replacement Name: Ischaemum rottboellioides R. Br., Prodr. 1: 205 (1810).
Type of Basionym or Protologue Information: Australia: Queensland: Bottom C Paddock, Swans Lagoon, 24 Mar 1983, P. Chaplain s.n. [AQ349053] (HT: BRI).
Recent synonyms: Coelorachis rottboellioides.
Key references (books and floras): [1810]. R.Brown, Prodromus (205 as Ischaemum rottboellioides), [1878] G.Bentham, Flora Australiensis 7 (514 as Rottboellia ophiuroides), [1952] C.A.Gardner, Flora of Western Australia 1 Gramineae (304 as Coelorachis), [1969] E.E.Henty, Manual Grasses New Guinea (53 as Coelorhachis), [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of Australia.
Illustrations: [1952] C.A.Gardner, Flora of Western Australia 1 Gramineae (305, Pl.89 as Coelorhachis).
Habit. Perennial. Rhizomes present. Culms erect, 100–300 cm tall. Mid-culm nodes glabrous. Lateral branches branched. Ligule an eciliate membrane or a fringed membrane, a ciliate membrane, 1 mm long. Leaf-blades 20–50 cm long, 8–20 mm wide.
Inflorescence. Inflorescence compound, composed of rames. Peduncle distinct. Rhachis fragile at the nodes.
Spikelets. Spikelets sessile, 1 in the cluster. Companion spikelets pedicelled, 1 in the cluster. Companion spikelets developed, male, 3–4 mm long. 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, ovate, dorsally compressed, 3–4.5 mm long.
Glumes. Glumes dissimilar, firmer than fertile lemma. Lower glume elliptic or oblong or ovate, coriaceous or indurate, keeled, 2-keeled, winged on keel, winged broadly. Upper glume elliptic or oblong, membranous or coriaceous, keeled, 1-keeled. Upper glume apex mucronate. Florets. Basal sterile florets 1, barren, with palea. Lemma of lower sterile floret hyaline.
Fertile lemma without keel.
Continental Distribution: Tropical Asia and Australasia.
Australian Distribution: Western Australia, Northern Territory, Queensland.
Western Australia: Gardner, Fitzgerald, Dampier. Northern Territory: Darwin & Gulf, Victoria River. Queensland: Burke, Cook, Leichhardt, North Kennedy, South Kennedy.
Notes. Widely encountered although only locally common, in grasslands or open forests of tropical Australia, extending to New Guinea, Indonesia and the Philippines. Flowers Dec.--June.
