Sporobolus is a perennial grass colonizing open areas and hard substrates. There is some die-back of older plants in the winter. It is characterized by broad tapering blades, and a relatively closed seed head on a long stalk. It is abundant on the runway, and common on the roads and in other open sandy areas.
Sporobolus cotyledons are relatively long and narrow, the second and following blades are generally broad and tapering. At this stage, it is very small, which can be used to distinguish it from other broad-bladed grasses such as Setaria.
Sporobolus continues to produce short, broad, highly tapered blades, with new stems radiating out from the base. The leaf shape and size is sufficient to distinguish it from all other grasses on Kure.
Description: Low, tufted perennial. Culms numerous, often spreading at base, glabrous, mostly 10-50 cm tall. Sheaths glabrous or with a few hairs on the upper margins. Ligule a fringe of hairs on a membranous collar, 0.5-0.8 mm long. Blades flat, 3-12 (-20) cm long and mostly 2-4 mm broad, usually ciliate on lower margins and sparsely hispid on adaxial surface. Panicles open, more or less pyramidal, mostly 3-15 (-18) cm long and 2-5 cm broad at base, the lower and middle branches in whorls and bare of spikelets on the lower 1/3-1/2. Spikelets 1.5-2.0 mm long, the lateral ones on very short pedicels. Glumes very unequal, thin, acute, the first 0.3-0.8 mm long, the second as long as the lemma. Lemma acute, glabrous or scabrous. Palea hyaline, slightly shorter than the lemma. Grain broadly oblong, flattened laterally, usually 0.6-0.9 mm