Derivation
Triodia R.Br., Prodr. 182 (1810); from the Greek treis (three) and odous (tooth), referring to the 3-toothed or 3-lobed lemmas.

microstachya- from the Greek mikros (small) and stachys (ear of corn). Inflorescences or spikelets small.

Published in
Prodr. 182 (1810).

Habit
Perennial, densely tufted. Stolons present. Culms 30–250 cm tall. Leaf-sheaths resinous, glabrous on surface. Ligule a fringe of hairs. Leaf-blade base without a false petiole. Leaf-blades curved or curled, aciculate, flat or conduplicate, 60 cm long, 0.5–1.3(–4.5) mm wide, rigid, resinous, without scent or aromatic. Leaf-blade venation with continuous uniform subepidermal sclerenchyma layer on the underside (except median line). Leaf-blade margins scabrous.

Inflorescence
Inflorescence compound, a panicle of racemes. Panicle open or contracted, 18–74 cm long, 1–8 cm wide, contracted about primary branches. Primary panicle branches 4–8 cm long. Panicle axis scabrous. Panicle branches bearing approximate spikelets or distant spikelets, scabrous.

Spikelets
Spikelets solitary. Fertile spikelets many flowered, comprising 3–4 fertile florets, with diminished florets at the apex, oblong, laterally compressed or terete, 3–6 mm long, breaking up at maturity. Spikelets disarticulating below each fertile floret. Spikelet callus glabrous, base obtuse.

Glumes
Glumes persistent, similar, thinner than fertile lemma. Lower glume oblong, 2.8–5 mm long, 120% length of upper glume, scarious, 3-nerved, midnerve scabrous. Lower glume surface scabrous, rough on nerves. Lower glume apex acute. Upper glume oblong, 2.3–3.5 mm long, 100% of length of adjacent fertile lemma, scarious, 1–3-nerved. Upper glume lateral nerves absent or distinct. Upper glume surface smooth. Upper glume apex acute.

Florets
Fertile lemma oblong, 2–3.5 mm long, cartilaginous or coriaceous, 3-nerved. Lemma surface glabrous or hirsute. Lemma margins pubescent, hairy below. Lemma apex dentate or lobed, 3-fid, with simple equal triangular lobes 0.2–0.5(–1) mm long, acute, muticous. Palea keels wingless or narrowly winged, ciliolate. Palea surface glabrous. Apical sterile florets resembling fertile though underdeveloped. Anthers 3, 1–2 mm long.

Continental Distribution:
Australasia.

Australian Distribution:
Western Australia, Northern Territory, Queensland.

Western Australia: Gardner, Fitzgerald, Hall, Dampier. Northern Territory: Darwin & Gulf, Victoria River. Queensland: Cook, Burke, North Kennedy, South Kennedy, Leichhardt.

Classification. (GPWG 2001):
Chloridoideae: Triodieae

Notes
Native. North of 20°S on mainland and coastal islands. Widespread and often the dominant grass in deep or skeletal, sandy or yellow earth soils on rugged, dissected often bouldery, sandstone plateaux, hills, ranges, ridges, mesas, escarpments, ravines, gorges, creek valleys and massive outcrops; also associated with quartzite, basalt, laterite and conglomerate, and found on coastal sands and beach dunes, coastal pindan, salt lakes, in white alluvial sand near creeks, and in rocky creek river beds; flowers Jan.–May, persisting into June to Oct.