Themeda helferi

HABIT Annual; culms solitary, or caespitose; clumped loosely. Culms erect, or geniculately ascending; slender; 15–30 cm long. Leaf-sheaths mostly shorter than adjacent culm internode; glabrous on surface. Ligule an eciliate membrane; 1 mm long; truncate. Leaf-blades flat, or conduplicate; 5–10 cm long; 2–4 mm wide; flaccid. Leaf-blade surface smooth; glabrous. Leaf-blade margins tuberculate-ciliate; hairy at base. Leaf-blade apex acute.

INFLORESCENCE Synflorescence compound; scanty; 15–30 cm long (whole culm); with principal spatheoles embracing a compact fascicle of racemes, each subtended by a subsidiary bract. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; enclosed. Spatheole lanceolate; 2 cm long; scarious; without tubercles; glabrous.

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; 2 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; male; lanceolate; 4–5 mm long; equalling fertile, or larger than fertile. Basal sterile spikelet glumes chartaceous; tuberculate; setose; lower glume muticous.

Companion sterile spikelets well-developed; comprising 2 subequal glumes without lemmas; linear; 5–6 mm long; longer than 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; 4 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus oblong; 0.5–1 mm long; 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; much thinner above; without keels. Lower glume surface flat; puberulous. Upper glume oblong.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; hyaline. Fertile lemma linear; hyaline; without keel; 1 -veined. Lemma apex entire; awned; 1 -awned. Principal lemma awn apical; geniculate; 3.8–5.5 mm long overall; with twisted column. Column of lemma awn hirtellous. Palea absent or minute.

DISTRIBUTION Asia-temperate: China. Asia-tropical: Indo-China.

NOTES Andropogoneae. Fl China 2001.

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