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).
A slender annual otherwise resembling H. incana, has been collected (as an introduction from Europe) in Md.