Themeda gigantea

HABIT Perennial; caespitose. Culms erect; robust; 150–400 cm long. Culm-internodes solid; distally pruinose, or glabrous. Leaf-sheaths keeled; glabrous on surface; outer margin glabrous, or hairy. Ligule a ciliolate membrane; truncate, or obtuse. Leaf-blades 30–100 cm long; 5–25 mm wide; stiff. Leaf-blade midrib widened. Leaf-blade surface scabrous; rough adaxially; glabrous. Leaf-blade margins scabrous.

INFLORESCENCE Synflorescence compound; paniculate. Inflorescence composed of racemes; terminal and axillary; deciduous as a whole; subtended by a spatheole; enclosed. Spatheole lanceolate; 1–1.2 cm long; scarious; without tubercles; glabrous. Peduncle 0.1–0.2 cm long.

Racemes 1; single; ovate; 1 cm long; bearing a triad of spikelets; bearing 1 fertile spikelets on each. Rhachis tough.

Spikelets in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Pedicels linear; 1–1.5 mm long.

STERILE SPIKELETS Basal sterile spikelets well-developed; 4 in number; forming an involucre about the fertile; with normal internodes (between them); subsessile; deciduous with the fertile; male; lanceolate, or oblong; 6.5–8 mm long; equalling fertile. Basal sterile spikelet glumes tuberculate; hirsute; with tawny hairs; acuminate; lower glume muticous.

Companion sterile spikelets well-developed; male; lanceolate; 4–5 mm long; shorter than fertile; deciduous with the fertile. Companion sterile spikelet callus indistinct. Companion sterile spikelet glumes tuberculate; hirsute; with tawny hairs. Companion sterile spikelet lemmas 2; enclosed by glumes; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; compressed slightly; 6.5–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus oblong; bearded; base obtuse; attached obliquely. Spikelet callus hairs tawny.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; dark brown; without keels; 5–7 -veined. Lower glume surface flat; pubescent. Lower glume hairs tawny. Lower glume apex acute. Upper glume oblong; coriaceous.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; hyaline. Fertile lemma lanceolate; hyaline; without keel; 1 -veined. Lemma apex entire; acute; muticous, or awned; 1 -awned. Principal lemma awn 0–10 mm long overall. Palea absent or minute.

FLOWER Anthers 3.

DISTRIBUTION Asia-tropical: Indo-China, Malesia, and Papuasia. Pacific: southwestern.

NOTES Andropogoneae. WDC 1996.

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