Andropogon gayanus

HABIT Perennial; caespitose. Culms 150–250 cm long. Ligule an eciliate membrane. Collar without external ligule, or with external ligule. Leaf-blade base tapering to the midrib; without a false petiole, or with a false petiole. Leaf-blades 30–60 cm long; 4–20 mm wide.

INFLORESCENCE Synflorescence compound; paniculate; lax. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole. Spatheole lanceolate; 6–8 cm long; herbaceous.

Racemes 2; paired; 4–9 cm long. Rhachis fragile at the nodes; glabrous on surface; ciliate on margins. Rhachis internodes cuneate. Rhachis internode tip transverse; crateriform; with simple rim.

Spikelets appressed; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels cuneate; 4–5 mm long; ciliate; tip lobed.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; elliptic; dorsally compressed; 5–8 mm long; as long as fertile. Companion sterile spikelet glumes chartaceous; glabrous, or pubescent, or villous; acute; awned; one glume awned, or both glumes awned; with 1–10 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 oblong; dorsally compressed; 5–8 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus oblong; 1 mm long; pilose; base obtuse; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; 2-keeled; keeled laterally. Lower glume intercarinal veins distinct. Lower glume surface flat and with a longitudinal median groove; glabrous. Upper glume lanceolate; chartaceous; 1-keeled. Upper glume muticous, or mucronate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; hyaline; 2 -veined. Fertile lemma oblong; hyaline; without keel. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 10–30 mm long overall; with twisted column. Column of lemma awn glabrous.

DISTRIBUTION Africa: Macaronesia, west tropical, west-central tropical, northeast tropical, east tropical, southern tropical, and south. Asia-tropical: Indo-China. Australasia: Australia. South America: northern South America, western South America, and Brazil.

NOTES Andropogoneae. FTEA.

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