Setaria tenacissima

HABIT Annual. Culms geniculately ascending; 100–200 cm long; without nodal roots, or rooting from lower nodes. Culm-nodes glabrous. Leaf-sheaths antrorsely scabrous; outer margin hairy. Ligule a fringe of hairs. Collar pilose. Leaf-blades flat, or conduplicate; 10–20 cm long; 4–10 mm wide. Leaf-blade surface scabrous; rough on both sides; pubescent; hairy on both sides.

INFLORESCENCE Inflorescence a panicle. Peduncle scaberulous above.

Panicle spiciform; linear; loose; 10–20 cm long. Primary panicle branches 0.2–0.5 cm long; sterile at the tips. Panicle axis angular; pilose. Panicle branches pubescent.

Spikelets subtended by an involucre. Fertile spikelets pedicelled; 1 in the cluster. Involucre composed of bristles; 10–15 mm long. Involucral bristles persistent; 1 per spikelet; rigid; retrorsely scaberulous; retrorse above, antrorse below; glabrous. Pedicels oblong.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; 1.4–1.8 mm long; falling entire.

GLUMES Glumes shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 0.5 length of spikelet; membranous; without keels; 3 -veined. Lower glume apex acute. Upper glume ovate; 0.9 length of spikelet; membranous; purple; without keels; 5 -veined. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret ovate; 1 length of spikelet; membranous; purple; 5 -veined; acute. Fertile lemma ovate; dorsally compressed; gibbous; 1.2–1.4 mm long; indurate; without keel. Lemma surface rugose. Lemma margins involute. Palea involute; indurate.

DISTRIBUTION South America: Mesoamericana, Caribbean, northern South America, western South America, and Brazil.

NOTES Paniceae. Rominger 1994.

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