Plants annual or perennial; cespitose, sometimes rhizomatous. Culms to 10(25) cm. Sheaths open, usually glabrous, lower sheaths shorter than the upper sheaths; auricles absent; ligules 2-6 mm, membranous. Inflorescences contracted panicles, some branches longer than 1 cm. Spikelets pedicellate, 2.5-5 mm, laterally compressed, with 2(3) florets, all florets bisexual or some florets bisexual and others pistillate; disarticulation above the glumes, beneath the florets. Glumes equal or subequal, usually exceeding all the florets, sometimes subequal to them, ovate or acuminate, margins scarious, apices unawned; lower glumes 1-veined; upper glumes 3-veined; calluses poorly developed, glabrous; lemmas oval or elliptic, 3(5)-veined, lateral veins near the margins, glabrous, scabrous, or pilose, apices acute or obtuse, sometimes denticulate, unawned; paleas slightly shorter than the lemmas; lodicules 2; anthers 3. Caryopses shorter than the lemmas, concealed at maturity, x = unknown.
Discussion
Dissanthelium contains about 20 species, and has an amphi-neotropical distribution. Most species grow in South America; two grow in North America. One of the two North American species, D. matbewsii (Ball) R.C. Foster & L.B. Sm., has a disjunct distribution, growing in both central Mexico and South America. The other, D. californicum, is discussed below.