Derivation
Themeda Forssk., Fl. Aegypt.-Arab. 178 (1775); from the Arabic thaemed (little water), possibly referring to water storage cells on the upper surface of the leaves or to the habitat of the type specimen in Yemen, fide L.K.A.Chippindall & A.O.Crook, Grasses of Southern Africa (1976).

arguens- from the Latin arguo (content).

Published in
Monog. Phan. 6: 657 (1889).

Common synonyms
Themeda frondosa (R.Br.) Merr.

Habit
Annual, tufted. Culms erect or geniculately ascending, 20–300 cm tall. Leaves mostly basal. Ligule an eciliate membrane, 1 mm long. Leaf-blade base broadly rounded. Leaf-blades flat or conduplicate, 5–30 cm long, 4–7 mm wide. Leaf-blade apex acuminate.

Inflorescence
Inflorescences arranged within a synflorescence. Inflorescence terminal and axillary, subtended by a spatheole, enclosed. Spatheole lanceolate, 2.5–4 cm long, scarious, without tubercles or tuberculate, glabrous or pilose. Rames single, cuneate, bearing a few fertile spikelets, bearing 1 fertile spikelets on each. Rhachis fragile at the nodes.

Spikelets
Spikelets in threes (basal paired). Pedicels oblong, 1 mm long, tip oblique. Basal sterile spikelets represented by a single scale, 4 in number, forming an involucre about the fertile, with both pairs arising at about the same level, subsessile. Basal sterile spikelets 6–10 mm long, equalling fertile. Basal sterile spikelet glumes smooth, glabrous. Basal sterile spikelet lower glume muticous. Companion spikelets developed, comprising 2 subequal glumes without lemmas, lanceolate, 6–10 mm long, shorter than fertile, separately deciduous. Companion spikelet callus linear, 2–3 mm long, truncate. Companion spikelet glumes herbaceous, glabrous, acuminate. Fertile spikelets 2-flowered, comprising 1 fertile floret, lower floret sterile, upper fertile, without rhachilla extension, elliptic, terete, 8–11 mm long, falling entire, deciduous with accessory branch structures. Spikelet callus linear, 3–4 mm long, bearded, base pungent, attached obliquely. Spikelet callus hairs red.

Glumes
Glumes dissimilar, firmer than fertile lemma. Lower glume oblong, equalling spikelet, coriaceous, dark brown, 7-nerved. Lower glume surface smooth, pilose or hispid, hairy above. Lower glume hairs dark brown. Lower glume apex truncate. Upper glume oblong, coriaceous, with membranous margins, 3-nerved. Upper glume surface pilose, hairy above. Upper glume margins ciliate. Upper glume hairs dark brown. Upper glume apex truncate.

Florets
Basal sterile floret 1, without significant palea. Lemma of lower sterile floret oblong, 2.8 mm long, hyaline, ciliate on margins. Fertile lemma oblong, 3 mm long, hyaline, 1-nerved. Lemma apex entire, 1-awned. Median (principal) awn apical, geniculate, 50–90 mm long overall, with a twisted column. Column hispidulous. Palea absent or minute. Anthers 1.4 mm long.

Continental Distribution:
Tropical Asia, Australasia, Pacific, South America.

Australian Distribution:
Western Australia, Northern Territory, Queensland.

Western Australia: Gardner. Northern Territory: Darwin & Gulf. Queensland: Burke, Cook, North Kennedy, South Kennedy.

Classification. (GPWG 2001):
Panicoideae: Andropogoneae

Notes
A fairly widespread tropical species from northern regions of W.A., N.T. and Qld and extending through SE Asia to the Andaman Is. Flowers Feb.–Sept.