Oxychloris Nuytsia 5: 283 (1985).
Derivation:. From Greek oxys (sharp) and the generic name Chloris (in which it was formerly included), referring to the pungent callus.
Taxonomic revisions, nomenclatural references:. M.Lazarides, Nuytsia 5: 283 (1985).
Key references (keys and floras):. M.Lazarides, F.Quinn and J.Palmer, Flora of the Kimberley Region 1195 (1992); B.K.Simon, Key to Australian Grasses 135 (1993); S.W.L.Jacobs and S.M.Hastings, Flora of New South Wales 4: 519–520 (1993); D.Sharp and B.K.Simon, AusGrass (2002); K.Mallet (ed.), Flora of Australia 44B: Poaceae 3: 284 (2005); J.P.Jessop, Grasses of South Australia 390 (2006); S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th ed, 311 (2008).
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (393).
Native, endemic. 1 species, from mainland Australia. WA, NT, SA, Qld, and NSW.
Habit. Annual or perennial (short-lived), tufted. Leaf blades narrow (less than 3.5 mm wide). Ligule a fringed membrane (short).
Inflorescence. Inflorescence of spicate main branches, of digitate or subdigitate racemes or spikes, digitate.
Spikelets. Spikelets laterally compressed, more than 2 flowered, with 1 fertile floret, solitary, subsessile to pedicelled (on one side of axis); with naked rachilla extension (and modified with spongy tissue to form a conspicuous thickened inernode, separating the clustered sterile florets from the basal fertile one). Fertile spikelets falling with glumes (the spikelets falling whole), with distinctly elongated rachilla internodes between florets.
Glumes. Glumes unequal, long relative to adjacent lemmas, hairless, glabrous, pointed (lower glume) or truncate (upper glume), awnless, keeled, similar (thinly membranous to hyaline, often purple-tinged). Lower glume 1 nerved. Upper glume 1 nerved.
Florets. Fertile florets 1 (basal). Lemmas decidedly firmer than glumes (cartilaginous to indurated), not becoming indurated (but dark brown when mature), incised, awned, without a germination flap, 3 nerved (the laterals submarginal), with nerves confluent towards tip, hairy, 1 keeled (the mid-nerve ribbed). Awns 1, dorsal, non-geniculate, hairless, about as long as body of lemma to much longer than body of lemma. Lemma hairs in tufts (from near the apices of the lateral nerves and lower on the mid-nerve). Palea relatively long, apically notched, 2 nerved. Palea keels winged (the wings ciliate). Distal incomplete florets 3–5, specialised and modified (the clustered sterile lemmas large, winged and awned, the lower ones broad, flaring and 7 nerved). Callus long, pointed. Stamens 3. Grain small, trigonous. Hilum short. Embryo large (almost as long as the fruit).
Kranz Anatomy. C4, biochemical type NAD-ME (1 species).
Habitat. Xerophytic. Dry savanna. Species of open habitats.
Classification. Chloridoideae; Cynodonteae.
Notes. After continued research on generic boundaries within the tribe [Chlorideae], I am elevating the taxon [to generic rank] on the basis of its elongated, pungent callus, a unique feature within the subfamily Chloridoideae, and its 4–6-flowered, winged spikelet, which more closely resembles the spikelet of Tetrapogon than that of Chloris (Lazarides, 1985).
Types Species. O. scariosa (F.Muell.) Lazarides.
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Endemic.