Themeda quadrivalvis

HABIT Annual. Culms erect, or geniculately ascending; 30–200 cm long; 4–6 mm diam.; 5–7 -noded; with prop roots. Culm-nodes glabrous. Leaf-sheaths keeled. Ligule an eciliate membrane; 2–2.5 mm long. Leaf-blades 7–30 cm long; 3–6 mm wide; flaccid. Leaf-blade surface smooth, or scaberulous; rough adaxially; glabrous, or pilose. Leaf-blade margins scabrous. Leaf-blade apex acute, or acuminate.

INFLORESCENCE Synflorescence compound; fasciculate; 15–50 cm long. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; enclosed. Spatheole lanceolate; 7.5–16 cm long; scarious; red; without tubercles, or tuberculate; glabrous, or pilose. Peduncle 1.3 cm long.

Racemes 1; single; cuneate; bearing few fertile spikelets; bearing 1 fertile spikelets on each. Rhachis fragile at the nodes.

Spikelets in threes (basal paired). Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels oblong; 0.5 mm long.

STERILE SPIKELETS Basal sterile spikelets well-developed; 4 in number; forming an involucre about the fertile; with both pairs arising at about the same level; subsessile; linear, or lanceolate; 4.5–6 mm long; equalling fertile. Basal sterile spikelet glumes chartaceous; tuberculate on margins and setose on margins; lower glume muticous.

Companion sterile spikelets well-developed; comprising 2 subequal glumes without lemmas; linear; 5–6 mm long; as long as fertile; separately deciduous. Companion sterile spikelet callus linear. Companion sterile spikelet glumes smooth; glabrous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; subterete; 5–5.5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus oblong; bearded; base obtuse; attached obliquely. Spikelet callus hairs red.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; much thinner above; dark brown; without keels; 7–9 -veined. Lower glume surface puberulous. Lower glume apex obtuse. Upper glume oblong; 3 -veined. Upper glume margins ciliolate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 3 mm long; hyaline; 1 -veined; without lateral veins. Fertile lemma linear; hyaline; without keel; 1 -veined. Lemma apex entire; awned; 1 -awned. Principal lemma awn apical; geniculate; 10–45 mm long overall; with twisted column. Column of lemma awn hirtellous. Palea absent or minute.

DISTRIBUTION Africa: northeast tropical, south, and western Indian ocean. Asia-temperate: western Asia, Arabia, and China. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia. Pacific: southwestern. North America: southwest USA and southeast USA. South America: Caribbean and southern South America.

NOTES Andropogoneae. FTA.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.