Setaria macrosperma

HABIT Perennial; short-lived. Culms erect, or geniculately ascending; robust; 100–150 cm long; without nodal roots, or rooting from lower nodes. Culm-internodes distally glabrous. Culm-nodes glabrous. Leaf-sheaths keeled; glabrous on surface; outer margin hairy. Ligule a fringe of hairs; 1–3 mm long. Collar pubescent. Leaf-blades flat, or conduplicate; 35–50 cm long; 10–20 mm wide. Leaf-blade surface scabrous; rough on both sides; glabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform; lanceolate; loose; 10–25 cm long. Primary panicle branches ascending; 1.5–3 cm long; sterile at the tips. Panicle axis angular; scabrous; villous.

Spikelets subtended by an involucre. Fertile spikelets pedicelled; 1 in the cluster. Involucre composed of bristles; 15–30 mm long. Involucral bristles persistent; 1–2 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; 3–3.2 mm long; falling entire.

GLUMES Glumes shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 0.33 length of spikelet; membranous; without keels; 3 -veined. Lower glume apex acute; mucronate. Upper glume ovate; 0.75 length of spikelet; membranous; without keels; 3–7 -veined. Upper glume apex acute; mucronate.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret ovate; 1 length of spikelet; membranous; 5 -veined; acute. Palea of lower sterile floret 0.5 length of lemma. Fertile lemma ovate; dorsally compressed; gibbous; 3 mm long; indurate; without keel. Lemma surface rugulose. Lemma margins involute. Palea involute; indurate.

DISTRIBUTION North America: southeast USA. South America: Caribbean.

NOTES Paniceae. Rominger 1994.

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