Schizachyrium scoparium

HABIT Perennial; caespitose. Rhizomes absent, or short. Culms 50–150 cm long. Lateral branches ample. Leaf-sheaths keeled; glabrous on surface to hirsute. Ligule an eciliate membrane; 1–3 mm long. Leaf-blades 15–30 cm long; 3–6 mm wide. Leaf-blade surface glabrous to hirsute. Leaf-blade apex acute.

INFLORESCENCE Synflorescence compound; linear. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; exserted. Spatheole linear; 4–6 cm long; herbaceous.

Racemes 1; single; sinuous; 3–6 cm long. Rhachis fragile at the nodes; semiterete; ciliate on margins, or villous on margins. Rhachis internodes clavate. Rhachis internode tip cupuliform; with scarious rim.

Spikelets ascending, or spreading; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; curved; ciliate, or villous.

STERILE SPIKELETS Companion sterile spikelets represented by single glumes, or well-developed; comprising 2 subequal glumes without lemmas, or containing empty lemmas, or male; lanceolate; dorsally compressed; 1.5–7 mm long; shorter than fertile; deciduous with the fertile. Companion sterile spikelet glumes chartaceous; muticous, or awned; one glume awned; with 1.5–3 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 lanceolate; dorsally compressed; 6–8 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 all along; keeled laterally; keeled obtusely. Lower glume intercarinal veins distinct; 3 in number. Lower glume surface flat, or concave. Upper glume lanceolate; membranous; 1-keeled.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; hyaline; 2 -veined. Fertile lemma oblong; hyaline; without keel; 1 -veined. Lemma apex lobed; 2 -fid; with lanceolate lobes; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 8–15 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

DISTRIBUTION Asia-tropical: India. 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.

NOTES Andropogoneae. Fl Pak 1993.

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