Hyparrhenia exarmata

HABIT Perennial; caespitose. Butt sheaths glabrous. Culms erect; 150 cm long. Leaves cauline. Ligule an eciliate membrane; 1–2 mm long. Leaf-blades 30–60 cm long; 4–9 mm wide. Leaf-blade surface glabrous, or pilose.

INFLORESCENCE Synflorescence compound; paniculate; 20–40 cm long. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; exserted. Spatheole linear, or lanceolate; 3–6 cm long; membranous; red. Peduncle pubescent above, or pilose above.

Racemes 2; paired; erect; 1.5–2.5 cm long; bearing 6–10 fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis hairs red. Rhachis internodes linear. Rhachis internode tip oblique; flat. Raceme-bases filiform; unequal (the longer measured); 3 mm long; glabrous.

Spikelets appressed; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; flattened; ciliate; with red hairs; tip oblique; toothed (0.1–0.2mm).

STERILE SPIKELETS Basal sterile spikelets well-developed; 2 in number (lower raceme); 0 in upper raceme; lanceolate; 3.5–5 mm long; equalling fertile. Basal sterile spikelet glumes smooth on margins; lower glume muticous.

Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 3 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; acute; muticous. 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; 3.5–4 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus square; 0.25 mm long; pubescent; base obtuse; attached obliquely. Spikelet callus hairs red.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma; shiny. Lower glume lanceolate; 1 length of spikelet; coriaceous; red; without keels; keel-less except near apex. Lower glume surface pubescent. Lower glume hairs red. 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; 3 mm long; 1 length of fertile lemma; hyaline; 0 -veined; without midvein; without lateral veins; ciliate on margins. Fertile lemma ovate; 3 mm long; membranous; without keel; 1 -veined. Lemma margins ciliate. Lemma apex entire; truncate; mucronate. Palea absent or minute.

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

DISTRIBUTION Africa: west tropical, west-central tropical, northeast tropical, and east tropical.

NOTES Andropogoneae. WDC.

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