Hyparrhenia diplandra

HABIT Perennial; caespitose. Butt sheaths glabrous. Culms erect; robust; 200–300 cm long. Leaves cauline. Leaf-sheaths glabrous on surface, or pilose. Leaf-sheath oral hairs bearded (grey hairs). Ligule an eciliate membrane; 1–2 mm long. Leaf-blades 20–60 cm long; 3–10 mm wide. Leaf-blade surface glabrous, or hirsute; sparsely hairy; hairy abaxially.

INFLORESCENCE Synflorescence compound; paniculate; 20–40 cm long. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; enclosed. Spatheole lanceolate; 2–4.5 cm long; membranous; brown, or red; glabrous. Peduncle 0.3–1.5 cm long; glabrous, or hirsute above.

Racemes 2; paired; deflexed; 1.5–2(–2.5) cm long; bearing few fertile spikelets; bearing (1–)2–3(–5) fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis internodes linear. Rhachis internode tip oblique; flat. Raceme-bases flattened; subequal; 1–2 mm long; pubescent.

Spikelets appressed; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; flattened; ciliate; tip oblique.

STERILE SPIKELETS Basal sterile spikelets well-developed; on lower raceme 4 in number; 4 in upper raceme; forming an involucre about the fertile; lanceolate; 7–9 mm long; larger than fertile. Basal sterile spikelet glumes scabrous on margins; lower glume muticous.

Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 5–7.5 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; acute; muticous, or awned; one glume awned; with 0–5 mm long awn. Companion sterile spikelet lemmas 2; enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 6–8 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; 1.5 mm long; pubescent; base acute; attached obliquely.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; coriaceous; without keels; keel-less except near apex. Lower glume surface glabrous, or pubescent. Lower glume apex dentate; 2 -fid. Upper glume linear; coriaceous; without keels.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 1 length of fertile lemma; hyaline; 2 -veined. Fertile lemma linear; membranous; without keel; 1 -veined. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 20–55 mm long overall; with twisted column. Column of lemma awn pubescent; with 0.2–0.5 mm long hairs. Palea absent or minute.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3. Stigmas 2.

DISTRIBUTION Africa: west tropical, west-central tropical, northeast tropical, east tropical, southern tropical, and western Indian ocean. Asia-temperate: China. Asia-tropical: Indo-China and Malesia.

NOTES Andropogoneae. WDC.

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