Hyparrhenia dybowskii

HABIT Annual. Butt sheaths glabrous. Culms erect; robust; 100–200 cm long. Culm-nodes glabrous, or bearded. Leaves cauline. Leaf-sheaths outer margin hairy. Ligule an eciliate membrane; 1–4 mm long. Leaf-blades 25–35 cm long; 6–12 mm wide. Leaf-blade surface glabrous, or hirsute; sparsely hairy.

INFLORESCENCE Synflorescence compound; paniculate; 30 cm long. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; enclosed. Spatheole lanceolate; 6–9 cm long; membranous; glabrous, or hirsute (at base). Peduncle 0.5–4 cm long; glabrous, or pilose above.

Racemes 2; paired; deflexed; 3.5 cm long; bearing few fertile spikelets; bearing 1 fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis internodes linear. Rhachis internode tip oblique; flat. Raceme-bases flattened; subequal; 1.5 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; 15–25 mm long; equalling fertile. Basal sterile spikelet glumes scabrous on margins; lower glume muticous.

Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 15–19 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; acute; awned; one glume awned; with 2–5 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 linear, or oblong; dorsally compressed; 16–20 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus linear; 6 mm long; pubescent; base pungent; attached obliquely.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; coriaceous; yellow; without keels; keel-less except near apex. Lower glume surface glabrous to villous. 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; 120–190 mm long overall; with twisted column. Column of lemma awn pubescent. Palea absent or minute.

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

DISTRIBUTION Africa: west-central tropical.

NOTES Andropogoneae. WDC.

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