Andropogon amethystinus

HABIT Perennial; culms solitary, or caespitose. Rhizomes absent, or elongated. Butt sheaths glabrous. Culms geniculately ascending, or decumbent; 8–60 cm long. Ligule an eciliate membrane. Leaf-blades flat, or convolute; 1–15 cm long; 1–4 mm wide. Leaf-blade midrib evident.

INFLORESCENCE Inflorescence composed of racemes; terminal.

Racemes 2; paired; 2–8 cm long. Rhachis fragile at the nodes; ciliate on margins, or villous on margins. Rhachis hairs white; 2 mm long. Rhachis internodes linear. 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 linear, or clavate; ciliate, or villous; with white hairs.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate, or ovate; dorsally compressed; 4–8 mm long; as long as fertile; persistent. Companion sterile spikelet glumes chartaceous; wingless, or winged on keels; acute; awned; one glume awned; with 1–3 mm long awn. Companion sterile spikelet lemmas enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate, or elliptic; dorsally compressed; 5–8.5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; 1 mm long; pilose; base obtuse; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate, or elliptic; 1 length of spikelet; chartaceous, or coriaceous; 2-keeled; keeled laterally; wingless, or winged on keel. Lower glume intercarinal veins distinct; 2–6 in number. Lower glume surface convex, or flat, or concave; glabrous to villous. Lower glume apex dentate; 2 -fid. Upper glume lanceolate; chartaceous; 1-keeled; keeled above. Upper glume awned; 1 -awned. Upper glume awn 2–6 mm long.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; hyaline; 2 -veined. Fertile lemma oblong; hyaline; without keel. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 10–15 mm long overall; with twisted column. Column of lemma awn glabrous. Palea hyaline; 0 -veined; without keels.

DISTRIBUTION Africa: west tropical, west-central tropical, northeast tropical, east tropical, southern tropical, and south. Asia-temperate: Arabia. Asia-tropical: India.

NOTES Andropogoneae. FTEA.

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