Setariopsis

Plants annual. Culms 20-80 cm, to about 1 mm thick, solid, branching above the base. Sheaths open; ligules of hairs; blades flat. Inflorescences terminal, panicles, 8-23 cm long, 0.8-2 cm wide, with pilose rachises; branches 0.5-1.5 cm, spikelets congested, shortly pedicellate, the pedicels subtended by a 3-10 mm, terete bristle; disarticulation below the glumes. Spikelets dor-sally compressed, with 2 florets, lower florets usually sterile, upper florets bisexual. Lower glumes about 1/4 as long as the spikelets, 5-7-veined, subclasping; upper glumes slightly shorter than the spikelets, 11-19-veined, indurate at maturity, constricted at the base, auriculate above the point of constriction; lower lemmas longer than the glumes, membranous but somewhat indurate at the base; lower paleas usually present, short; upper lemmas indurate, finely trans¬versely rugose, apiculate, margins clasping the paleas; upper paleas similar to the lemmas in length and texture; lodicules 2; anthers 3, purple; ovaries glabrous; style branches 2, free to the base. Caryopses ovate, plano-convex; embryos about 1/2 as long as the caryopses. x = 9.

Distribution

Ariz.

Discussion

Setariopsis includes two species, both of which were thought to be endemic to Mexico until the recent discovery of the following species in Arizona (Reeder 2001).

Selected References

Pohl, R.W. 1994. Setariopsis Scribner P. 364 in G. Davidse, M. Sousa S., and A.O. Chater (eds.). Flora Mesoamericana, vol. 6: Alismataceae a Cyperaceae. Universidad National Autonoma de Mexico, Instituto de Biologia, Mexico, D.F., Mexico. 543 pp.

Reeder, J.R. 2001. Noteworthy collections: Arizona. Madrono 48:212-213.

Lower Taxa

Setariopsis auriculata