Aristida gibbosa

HABIT Perennial. Culms (32–)45–90 cm long. Lateral branches lacking. Leaf-sheath oral hairs lacking, or bearded (deciduous hairs). Ligule a ciliolate membrane; 0.2–0.4 mm long. Collar glabrous. Leaf-blades straight; conduplicate; 10.5–42 cm long; 1.8–2.5 mm wide. Leaf-blade surface scabrous; rough adaxially; glabrous, or pilose; hairless except near base; sparsely hairy; hairy adaxially. Leaf-blade apex acute; antrorsely scabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; (8–)12–24 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 evident; straight; 0.2–0.3 mm long; pilose; obtuse.

GLUMES Glumes persistent; dissimilar (lower in general slightly longer than upper, sometimes subequal or lower slightly shorter than upper). Lower glume lanceolate; 5.2–11.8 mm long; 1 -veined. Lower glume primary vein scabrous. Lower glume apex acute (shortly awned). Upper glume lanceolate; 5–9.8 mm long; 1 -veined. Upper glume surface smooth. Upper glume apex entire; acute (shortly awned).

FLORETS Fertile lemma subterete; (4.5–)5–11.5 mm long; without keel; rounded throughout; 3 -veined. Lemma surface smooth; with a median groove (ventral,longitudinal). Lemma margins involute. Lemma apex awned; 3 -awned. Principal lemma awn straight; ascending; simple at base; with (8–)8.8–19.5 mm long limb; with twisted column. Column of lemma awn (1–)1.5–4 mm long. Lateral lemma awns ascending; (6–)7–14 mm long; shorter than principal.

DISTRIBUTION North America: Mexico. South America: Mesoamericana, northern South America, western South America, and Brazil.

NOTES Aristideae. LO-W 1993.

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