Hyparrhenia arrhenobasis

HABIT Perennial; caespitose. Butt sheaths glabrous. Culms erect; 30–160 cm long. Leaves cauline. Ligule an eciliate membrane. Leaf-blades 10–30 cm long; 2–5 mm wide; glaucous.

INFLORESCENCE Synflorescence compound; scanty. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; embraced at base by subtending leaf. Spatheole lanceolate; 4–6 cm long; scarious; yellow, or red, or purple. Peduncle nodding; 2–3 cm long; pilose above (yellow hairs).

Racemes 2; paired; erect; 1.5–2.5 cm long; bearing few fertile spikelets, or many spikelets; bearing 3–9 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; stiffly setose.

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 2 in number, or 4 in number; 2 in upper raceme, or 4 in upper raceme; lanceolate; 7–12 mm long; larger than fertile. Basal sterile spikelet glumes glabrous, or pilose; setose on margins (pectinately); lower glume muticous.

Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 7–9 mm long; longer than fertile; separately deciduous. Companion sterile spikelet callus square; 0.2 mm long; truncate. Companion sterile spikelet glumes chartaceous; pubescent, or pilose; setose on margins; acuminate; mucronate, or awned; one glume awned; with 1–3 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; 6–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; 1 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; pallid; without keels; keel-less except near apex. Lower glume surface convex, or concave; hispidulous, or villous; hairy generally, or on veins. Lower glume hairs dark brown. 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; 25–40 mm long overall; with twisted column. Column of lemma awn hispidulous; with 0.3–0.5 mm long hairs. Palea absent or minute.

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

DISTRIBUTION Africa: northeast tropical.

NOTES Andropogoneae. WDC.

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