Plants annual. Culms 8-45 cm, erect. Leaves usually mostly cauline, sometimes mostly basal; sheaths glabrous or pubescent; upper sheaths usually inflated; ligules 1.4-4.5 mm, dorsal surfaces scabridulous, apices truncate to acute, lacerate to erose; blades 3-15 cm long, 0.7-2.5 mm wide, flat, becoming involute, finely scabrous. Panicles 2-12 cm long, 0.4-2 cm wide, cylindrical, spikelike, dense, occasionally lobed or interrupted near the base, appearing bristly from the awns, usually exserted from the upper sheaths at maturity; branches 0.3-1.5 cm, scabrous to scabridulous, ascending to appressed, spikelet-bearing to the base and hidden by the spikelets; pedicels 0.3-3 mm. Spikelets lanceolate, greenish to yellowish, tinged with purple. Glumes equal to subequal, 2.5-5 mm, scabrous over the midvein and often scabridulous on the body, 1-veined, apices narrowly acuminate to awn-tipped, awns to 1.5 mm; callus hairs to 0.5 (1) mm, usually dense; lemmas 1.5-2.3 mm, scabrous, translucent to opaque, 5-veined, veins prominent distally, apices acute, veins extended into 2 (4) teeth, teeth 0.1-0.5 mm, awned from about midlength or above, awns 3.5-8 mm, geniculate; paleas absent, or to 0.2 mm and thin; anthers 3, 0.4-0.6 mm, often retained at the apices of the caryopses. Caryopses 0.9-1.3 mm; endosperm soft. 2n = 56.
Calif., Oreg., Wash., B.C.
Agrostis microphylla grows in thin, rocky soils, sandy areas, cliffs, vernal pools, and serpentine areas. It is a winter annual, flowering in late winter to spring, adapted to low-competition habitats with summer drought. It may be related to, or conspecific with, Agrostis hendersonii (see previous).
Agrostis microphylla grows mostly along the Pacific coast from British Columbia to northern Baja California, Mexico. Reports of A. microphylla from the Humboldt Mountains, Nevada, reflect Vasey's treat¬ment of a specimen of A. exarata as the type of a new variety, A. microphylla var. major Vasey.
"decumbent" is not a number.