Andropogon gerardii

HABIT Perennial; caespitose. Rhizomes absent, or short. Culms 80–200 cm long. Lateral branches sparse. Ligule a ciliolate membrane. Leaf-blades 10–30 cm long; 5–10 mm wide; mid-green, or glaucous. Leaf-blade surface glabrous, or hirsute. Leaf-blade margins scabrous.

INFLORESCENCE Inflorescence composed of racemes; terminal.

Racemes 2–7; paired, or digitate; 4–11 cm long. Rhachis fragile at the nodes; glabrous on surface; pubescent on margins, or ciliate on margins. Rhachis hairs 0.5–4 mm long. Rhachis internodes linear, or clavate. Rhachis internode tip transverse; cupuliform; with simple rim.

Spikelets ascending; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear, or clavate; pubescent, or ciliate; with 0.5–4 mm long hairs.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; elliptic; 7–11 mm long; as long as fertile. Companion sterile spikelet glumes chartaceous; glabrous; acute; muticous. Companion sterile spikelet lemmas enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 7–11 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; coriaceous; 2-keeled; keeled laterally. Lower glume intercarinal veins obscure. Lower glume surface flat, or concave, or grooved on either side of midvein. Upper glume lanceolate; coriaceous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume muticous.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; hyaline. Fertile lemma lanceolate; hyaline; without keel. Lemma apex lobed; 2 -fid; muticous, or awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 0–20 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

FLOWER Anthers 3.

DISTRIBUTION Europe: southwestern. Pacific: north-central. North America: western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, south-central USA, southeast USA, and Mexico. South America: Mesoamericana and Brazil.

NOTES Andropogoneae. Gr Texas 1993.

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