Aristida havardii

HABIT Perennial; caespitose; clumped densely. Culms erect; 15–40 cm long. Culm-internodes distally glabrous. Leaf-sheaths without keel; outer margin hairy. Leaf-sheath oral hairs pubescent. Ligule a fringe of hairs; 0.5 mm long. Leaf-blades involute; 5–15 cm long; 0.5–1.5 mm wide.

INFLORESCENCE Inflorescence a panicle; deciduous as a whole.

Panicle open; oblong; effuse; 6–18 cm long; 0.5 of culm length. Primary panicle branches spreading, or reflexed; 3–6 cm long. Panicle branches with prominent pulvini.

Spikelets spreading; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets linear; subterete; 8–13 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 0.5 mm long; pilose; obtuse.

GLUMES Glumes similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 8–13 mm long; 1 length of upper glume; membranous; 1 -veined. Lower glume lateral veins absent. Lower glume apex acuminate. Upper glume lanceolate; 8–13 mm long; 1.6–1.8 length of adjacent fertile lemma; membranous; 1 -veined. Upper glume lateral veins absent. Upper glume apex acuminate.

FLORETS Fertile lemma linear; subterete; 5–7 mm long; coriaceous; without keel; 3 -veined. Lemma margins convolute; covering most of palea. Lemma apex awned; 3 -awned. Principal lemma awn 3-branched; with 8–22 mm long limb; with a straight or slightly twisted column. Column of lemma awn 2–5 mm long. Lateral lemma awns 8–22 mm long; subequal to principal.

FLOWER Anthers 3.

DISTRIBUTION North America: southwest USA, south-central USA, and Mexico. South America: Mesoamericana.

NOTES Aristideae. Gr Tex 1993.

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