Plants tufted or solitary. Culms 7-70 cm; nodes 3-5, glabrous, darkened. Sheaths 0.6-10.5 cm, smooth or scabridulous and minutely papillose; ligules 1-7 mm, veined, erose to lacerate, scabridulous and minutely papillose; blades (0.8)1.5-20 cm long, (0.4)1.5-6 mm wide, antrorsely scabridulous, glabrous. Panicles (1.1)2-16.5 cm long, (1.5)3-37 mm wide; rachises glabrous; branches to 3.4 cm, appressed to ascending, antrorsely scabridulous, pedicels with enlarged apices. Rachilla extensions 0.3-0.6 mm, densely pubescent. Glumes antrorsely scabridulous and minutely papillose below, almost scabrous above, margins hyaline; lower glumes 3-7 mm; upper glumes 2.7-5.5 mm; lemmas 1-1.5 mm, appressed pubescent, unawned or awned, awns to 6 mm, column twisted; paleas 1-1.3 mm, glabrous; anthers 0.5-0.9 mm, yellow-orange or purple. Caryopses 0.8-1 mm long, 0.4-0.5 mm wide, glabrous. 2n = 14.

Native to southwest Asia and northeast Africa, Gastridium phleoides now grows in Australia, South Africa, North America, and South America on dry, often disturbed areas. In the Flora region it is established in Oregon and California; it has also been collected in Arizona, western Texas (US 843557, Texas, 1884, Nealley s.n.), Massachusetts, and South Carolina.

Gastridium phleoides has been mistakenly placed in G. ventricosum (Gouan) Schinz & Thell. in North America, but it differs in having densely pubescent lemmas and well-developed, densely pubescent rachilla extensions.