Aristida laevis

HABIT Perennial. Culms 40–130 cm long. Lateral branches lacking. Leaf-sheath oral hairs lacking, or scanty (deciduous). Ligule a ciliolate membrane; 0.2 mm long. Collar pubescent (continuous). Leaf-blades straight; flat, or conduplicate (less frequent); (8–)15–60 cm long; 1.7–3.5 mm wide. Leaf-blade surface scabrous; rough adaxially; glabrous. Leaf-blade apex acute; antrorsely scabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted (linear); 10–30 cm long.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets subterete; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; straight; 0.7–1 mm long; pilose; acute (subacute).

GLUMES Glumes persistent; dissimilar (lower shorter than upper). Lower glume lanceolate; (8–)10–15 mm long; 1 -veined. Lower glume primary vein scaberulous. Lower glume surface asperulous; rough generally. Lower glume apex setaceously attenuate. Upper glume lanceolate; (10–)15–20 mm long; 1 -veined. Upper glume surface smooth. Upper glume apex entire; setaceously attenuate; awned.

FLORETS Fertile lemma subterete; 10–14 mm long; without keel; rounded throughout; 3 -veined. Lemma surface smooth, or scaberulous; rough above. Lemma margins convolute. Lemma apex awned; 3 -awned. Principal lemma awn straight; ascending; simple at base; with (23–)25–40(–46) mm long limb; without a column. Lateral lemma awns ascending; (23–)25–40(–46) mm long; subequal to principal.

DISTRIBUTION South America: Brazil and southern South America.

NOTES Aristideae. LO-W 1993.

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