Annual herb, up to 0.06 m high. Flowers: in a single head of sessile spikelets; spikelets digitate or clustered, rarely solitary, narrowly ovate, leaf-bearing, yellowish green; glumes and nutlets abscising individually leaving a persistent rachilla; glumes many; Mar., Apr.
Annual herb, up to 120 mm tall. Spikes simply urnbelled (1-headed stems often occur). Spikelets digitate or clustered, rarely solitary. Leaf-bearing. Nut obovoid. Glumes reddish brown.