Plants annual, gray-green, densely pubescent. Stems prostrate to ascending, 4-20 cm. Leaves opposite proximally, often alternate distally; stipules 0.5-1.3 mm; blade elliptic to oblanceolate, 3-12 mm, hirsute or ciliate, ad-axial surface sometimes glabres-cent. Inflorescences axillary, leaf-opposed or on short branches, mostly 3-8-flowered. Flowers 0.9-1.8 mm, densely pubescent; calyx burlike; sepals equal or somewhat unequal, 0.8-1.5 mm, hirsute, hairs of perigynous zone hooked or tightly coiled, each sepal with 1-2 spinelike hairs at apex; stamens 2-3 or 5; staminodes petaloid, 0.4-0.6 mm; styles distinct or connate in proximal 1/3. Utricles 0.7-0.9 mm, ca. equaling sepals. 2n = 18, 36 (Europe). We are following J. R. Akeroyd (1993) rather than M. N. Chaudhri (1968) in treating Herniaria cinerea as an infraspecific taxon of H. hirsuta. We believe it more appropriate to recognize the differences at varietal level; intermediate conditions found in both European and North American populations weaken the distinctions.