Common name
Rats's Tail Grass
Whitegrass

Derivation
Sehima Forssk., Fl. Aegypt.-Arab. 178 (1775); from the Eyptian vernacular name of the type, fide H.T.Clifford, Etymological Dictionary of Grasses (1996). Named after the Arab sign Saehim, fide S.D.J.E.Senaratna, The Grasses of Ceylon (1956).

nervosum- from the Latin nervus (nerve) and -osa (abundance). With conspicuous nerves in the glumes or lemmas.

Published in
Fl. Trop. Afr. 9: 36 (1917).

Habit
Perennial, tufted. Culms erect, 30–100 cm tall, wiry. Mid-culm nodes glabrous or bearded. Ligule a fringe of hairs, 1–2 mm long. Leaf-blades 5–40 cm long, 2–7 mm wide, glaucous. Leaf-blade apex attenuate, filiform.

Inflorescence
Rames single, straight or arcuate, 3–12 cm long. Rhachis fragile at the nodes, flattened, ciliate on margins. Rame internodes cuneate, 3.5–4 mm long. Rame internode tip oblique, crateriform.

Spikelets
Spikelets squeezed between internode and pedicel, in pairs, one sessile and fertile and the other (companion) spikelet pedicelled. Pedicels cuneate, flattened, 3.5–4 mm long, ciliate on margins, tip rectangular. Companion spikelets developed, male, containing empty lemmas or male, lanceolate or elliptic, dorsally compressed, 6–10 mm long, as long as fertile, separately deciduous. Companion spikelet glumes coriaceous, distinctly nerved, 5–7-nerved, ciliate on margins, acute, muticous. Companion spikelet lemmas 2, enclosed by glumes, muticous. Fertile spikelets 2-flowered, comprising 1 fertile floret, lower floret male, upper fertile, without rhachilla extension, elliptic, laterally compressed, 6–10 mm long, falling entire, deciduous with accessory branch structures. Spikelet callus square, pilose, base obtuse, inserted.

Glumes
Glumes dissimilar, firmer than fertile lemma. Lower glume elliptic, asymmetrical, 100% of length of spikelet, cartilaginous or coriaceous, much thinner above, 2-keeled, keeled dorsally below, flaring to lateral above, wingless or winged on keel, winged narrowly, winged near apex, 6-nerved. Lower glume lateral nerves branching above. Lower glume intercarinal nerves absent below, prominent above. Lower glume surface deeply depressed. Lower glume surface glabrous. Lower glume apex dentate, 2-fid, mucronate. Upper glume elliptic, 6 mm long, membranous or chartaceous, 1-keeled, winged on keel, winged near apex, 3–5-nerved. Upper glume surface scabrous, rough on nerves. Upper glume margins ciliate. Upper glume apex acute, awned. Upper glume awn 9–16 mm long.

Florets
Basal sterile floret 1, with palea. Lemma of lower sterile floret oblong, 6 mm long, hyaline, 2-nerved, ciliate on margins. Palea of lower sterile floret hyaline. Fertile lemma lanceolate, 5 mm long, hyaline, 3-nerved. Lemma margins ciliate. Lemma apex lobed, 2-fid, with linear lobes, incised 30% of lemma length, 1-awned. Median (principal) awn from a sinus, geniculate, 20–40 mm long overall, with a twisted column. Column hispidulous, hairy on the spiral. Palea 5 mm long, 100% of length of lemma, hyaline, without keels. Anthers 3 mm long.

Continental Distribution:
Africa, Temperate Asia, Tropical Asia, Australasia.

Australian Distribution:
Western Australia, Northern Territory, Queensland, New South Wales.

Western Australia: Gardner, Fitzgerald, Hall, Dampier. Northern Territory: Darwin & Gulf, Victoria River, Barkly Tableland, Central Australia North. Queensland: Cook, Burke, North Kennedy, South Kennedy, Port Curtis, Leichhardt, Burnett, Wide Bay, Darling Downs, Moreton, Gregory North, Mitchell, Maranoa. New South Wales: North-Western Slopes.

Classification. (GPWG 2001):
Panicoideae: Andropogoneae

Notes
Native. Common in savanna country througout subtropical and tropical Australia in Qld, northern N.S.W., N.T. and W.A. Extends through New Guinea and SE Asia to India and tropical Africa. Poor quality fodder. Flowers all year.