Andropogon gyrans

HABIT Perennial; caespitose. Culms erect; 30–80 cm long. Ligule a ciliolate membrane. Leaf-blades flat, or conduplicate; 10–15 cm long; 3–4 mm wide.

INFLORESCENCE Synflorescence compound; fasciculate. Inflorescence composed of racemes; terminal and axillary; subtended by an inflated leaf-sheath and a spatheole; exserted, or enclosed. Spatheole lanceolate; 3–8 cm long. Peduncle flexuous; 1–15 cm long.

Racemes 2; paired; 3–4 cm long. Rhachis fragile at the nodes; plumose on surface; plumose on margins. Rhachis hairs 2–3 mm long. Rhachis internodes filiform; 8–10 mm long. Rhachis internode tip transverse; cupuliform; with simple rim.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; 8–10 mm long; 1.4 length of fertile spikelet; plumose.

STERILE SPIKELETS Companion sterile spikelets represented by barren pedicels.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4–5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pilose; base obtuse; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; membranous; 2-keeled; keeled laterally. Lower glume intercarinal veins absent. Lower glume surface concave. Upper glume linear; membranous; 1-keeled. Upper glume muticous.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; hyaline; 2 -veined; ciliate on margins. Fertile lemma lanceolate; hyaline; without keel. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 10–15 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

FLOWER Anthers 1.

DISTRIBUTION North America: north-central USA, northeast USA, south-central USA, southeast USA, and Mexico. South America: Mesoamericana and Caribbean.

NOTES Andropogoneae. Gr Tex 1993.

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