Setaria grisebachii

HABIT Annual. Culms erect, or geniculately ascending; slender; 50–100 cm long. Culm-internodes smooth, or scaberulous. Culm-nodes pubescent. Leaf-sheaths antrorsely scabrous; outer margin hairy. Ligule a fringe of hairs. Collar pilose. Leaf-blades lanceolate; 7–25 cm long; 5–15 mm wide. Leaf-blade surface scabrous; rough on both sides; puberulous; hairy on both sides. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle. Peduncle smooth, or scaberulous above.

Panicle spiciform; linear; interrupted; loose; 3–18 cm long. Primary panicle branches 0.5–2.5 cm long; sterile at the tips. Panicle axis angular; scabrous; pubescent.

Spikelets subtended by an involucre. Fertile spikelets pedicelled; 1 in the cluster. Involucre composed of bristles; 5–15 mm long. Involucral bristles persistent; 1 per spikelet; flexible; antrorsely scaberulous; glabrous. Pedicels oblong.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; 1.5–2.2 mm long; falling entire.

GLUMES Glumes reaching apex of florets; thinner than fertile lemma. Lower glume ovate; clasping; 0.5 length of spikelet; membranous; without keels; 3 -veined. Lower glume apex acute. Upper glume ovate; 1 length of spikelet; membranous; without keels; 5 -veined. Upper glume apex obtuse.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret ovate; 1 length of spikelet; membranous; 5 -veined; sulcate; acute. Palea of lower sterile floret 0.2–0.33 length of lemma. Fertile lemma ovate; dorsally compressed; gibbous; 1.4–2 mm long; indurate; without keel. Lemma surface rugulose. Lemma margins involute. Palea involute; indurate.

DISTRIBUTION North America: southwest USA, south-central USA, and Mexico. South America: Mesoamericana and western South America.

NOTES Paniceae. Rominger 1994.

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