Setaria chapmanii

HABIT Perennial; caespitose. Culms erect; slender; 40–100 cm long. Culm-nodes glabrous. Lateral branches lacking, or sparse. Leaf-sheaths wider than blade at the collar; glabrous on surface; outer margin hairy. Ligule a fringe of hairs. Leaf-blades erect; flat, or involute; 15–40 cm long; 2–5 mm wide; stiff. Leaf-blade surface scabrous; rough on both sides.

INFLORESCENCE Inflorescence composed of racemes.

Racemes borne along a central axis; distant; appressed; paucilateral; 1–3.5 cm long; bearing few fertile spikelets; bearing 8–15 fertile spikelets on each. Central inflorescence axis 15–35 cm long; tip with blunt extension. Rhachis subterete; terminating in a barren extension; extension bristle-like; extension 3–6 mm long. Spikelet packing abaxial; irregular.

Spikelets solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets obovate; dorsally compressed; subacute; 1.8–2.2 mm long; falling entire.

GLUMES Glumes reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 0.33 length of spikelet; membranous; without keels; 3 -veined. Lower glume apex obtuse. Upper glume elliptic; 1 length of spikelet; membranous; without keels; 5–7 -veined. Upper glume lateral veins with cross-veins. Upper glume apex obtuse.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret similar to upper glume; elliptic; 1 length of spikelet; membranous; 5–7 -veined; obtuse, or acute. Fertile lemma elliptic; 1.8–2.2 mm long; indurate; without keel. Lemma surface rugulose. Lemma margins involute. Lemma apex acute. Palea reflexed at apex; indurate. Palea surface rugose.

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

NOTES Paniceae. Rominger 1994.

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