Culms (7)10-30(40) cm tall, (0.4)0.7-1 mm thick, glabrous; nodes glabrous or villous. Ligules to 0.5 mm; blades (1.5)3-5(8) cm long, (0.5)1-1.5(2.5) mm wide, both surfaces sparsely pilose. Panicles 2-8(10) cm; branches with 2-10(16) shortly pedicellate spikelets. Spikelets 6-8(10) mm, purplish, with (4)6-12(20) florets; lower glumes 4-7 mm; upper glumes 6-9 mm, equaling or exceeding the lowest florets; lemmas 4-7 mm, purplish-green, awned from between the lobes, awns 2-4 mm, apices bilobed, lobes 1-2 mm, obtuse to acute; anthers 0.4-1 mm or (when monandrous) to 1.3 mm. Caryopses 1-1.4 mm. 2n = 16, 32.

Erioneuron avenaceumis common in rocky areas from the southwestern United States to central Mexico; it also grows in Bolivia and Argentina. North American plants belong to E. avenaceum (Kunth) Tateoka var. avenaceum. Stoloniferous plants occur in the Flora region, but they are most common in central Mexico.

Common Name: shortleaf woollygrass

Duration: Perennial

Nativity: Native

Lifeform: Graminoid

General: Small tufted perennial, 10-30 cm tall, stems 0.5-1 mm thick, glabrous, nodes glabrous or villous.

Vegetative: Leaves mostly pilose, often densely so around ligule and collar, 3-5 cm long, 1-1.5 mm wide, firm, usually flat with whitish, cartilaginous midrib and border.

Inflorescence: Panicle dense, spikelike 2-8 cm, spikelets mostly 6-8 mm, purplish, with 6-12 florets; lower glumes 4-7 mm, upper glumes 6-9 mm, equaling or exceeding lowest florets; glumes thin, lanceolate, glabrous; lemmas 4-7 mm, purplish-green, awned from between lobes, awns 2-4 mm, apices bilobed, lobes 1-2 mm, obtuse to acute; flowers summer and fall.

Ecology: Found in grasslands, rocky slopes and oak openings; 3,000-5,500 ft (914-1676 m).

Distribution: se AZ, c and s NM, w TX; south to MEX; also in S. America.

Notes: Distinguished as an erect perennial 10-30 cm tall with white-margined, leaves which come to a point and are almost entirely restricted to the base of the plant. The inflorescence is condensed in a cluster at the top of the mostly leafless culm and is a condensed panicle with many flowers (florets) per spikelet, each floret awned and with many long hairs which makes the inflorescence appear to be bursting open. Most of the florets become purplish. Flora of North America suggests that North American plants belong to var. avenaceum.

Ethnobotany: Unknown

Etymology: Erioneuron is form Greek erion, wool and neuron, nerve, meaning woolly-nerved, while avenaceum means oat-like.

Synonyms: Erioneuron grandiflorum

Editor: SBuckley 2010, FSCoburn 2014