Sporobolus R.Br.

Spikelets 1–2 mm long, dull green-grey, crowded in narrow spike-like panicles, awnless Sporobolus
Lowest branches of inflorescence not whorled (1 or 2 branches only)
Upper glume ± as long as lemma. Rhizomatous or stoloniferous perennials. Leaves often apparently in pairs; blades 4–7 cm long. Inflorescence 3–13 mm long, spike-like, dense. Spikelets 2–4 mm long
Leaves more than 1 mm wide. Coastal dunes in wet places. Fl. summer. Sand Couch Sporobolus virginicusvirginicus
Leaves 1 mm wide or less. Coast. Salt marshes. Fl. summer. Marine Couch Sporobolus virginicusminor