Plants annual. Culms 5-45 cm, branched above the base; internodes solid. Uppermost sheath open, often partially enclosing the inflorescences; auricles absent; ligules membranous, truncate; blades flat or convolute. Inflorescences single, terminal spikes, cylindrical, with solitary spikelets embedded in and radial to the rachises, the abaxial surface of the upper glumes exposed; disarticulation at the rachis nodes. Spikelets dorsiventrally compressed, with 1-2 florets, second floret reduced and sterile; rachillas sometimes prolonged beyond the base of the distal floret. Lower glumes absent from all but the terminal spikelets; upper glumes coriaceous, stiff, longer and firmer than the lemmas, rigid, 3-7(9)-veined, acute, unawned, sometimes mucronate; lower lemmas membranous, lanceolate, 3(5)-veined, unawned; paleas hyaline; anthers 1-3; lodicules 2, oblique, glabrous, fleshy basally. Caryopses shorter than the lemmas, oblong, somewhat dorsally compressed, with an apical appendage, concealed at maturity; embryos about 1/5 the length of the caryopses; hila short, linear, x = 13.
S.C., Calif., Oreg., Tex., La.
Hainardia is a monospecific European genus that grows in saline and alkaline soils. It resembles Parapbolis, which also occupies coastal salt marshes, but Parapholis differs in having spikelets with 2 glumes and culms with hollow internodes.