Aristida purpusiana

HABIT Perennial. Culms erect; slender; 50–60 cm long. Culm-internodes distally glabrous. Lateral branches ample. Leaf-sheaths glabrous on surface. Leaf-sheath oral hairs ciliate. Ligule a fringe of hairs. Leaf-blades involute; 5–10 cm long; 1–2 mm wide.

INFLORESCENCE Inflorescence a panicle.

Panicle open; pyramidal; 15–25 cm long. Primary panicle branches spreading, or reflexed; 5–6 cm long.

Spikelets solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 10 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 1 mm long; pubescent; obtuse.

GLUMES Glumes similar; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate; 6 mm long; 0.75 length of upper glume; membranous; 1 -veined. Lower glume lateral veins absent. Lower glume apex emarginate. Upper glume lanceolate; 5 mm long; 0.75 length of adjacent fertile lemma; membranous; 1 -veined. Upper glume lateral veins absent. Upper glume apex emarginate.

FLORETS Fertile lemma linear; subterete; 10 mm long; coriaceous; without keel; 3 -veined. Lemma surface asperulous; rough above. Lemma margins convolute; covering most of palea. Lemma apex awned; 3 -awned. Principal lemma awn 3-branched; recurved at base of limb; with 8 mm long limb; with twisted column. Column of lemma awn 10 mm long. Lateral lemma awns 0.5–1 mm long; shorter than principal.

FLOWER Anthers 3.

DISTRIBUTION North America: Mexico.

NOTES Aristideae. Gr Baja Cal 1994.

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