Plants annual or short-lived perennial, often densely matted; taproot filiform to slender. Stems prostrate to ascending, dichot-omously branched, 5-20 cm, often retrorsely pubescent on 1 side. Leaves: stipules ovate-lanceolate, 1-1.5 mm, apex obtuse to acuminate, fimbriate; blade oblong to triangular-ovate, 1.5-6 × 0.5-1.5 mm, leathery, apex acute to obtuse, glabrous. Cymes terminal, 7-25+-flowered, much-branched and very profusely developed along all branches, 1.5-20 mm wide. Flowers 5-merous, occasionally 3- or 4-merous, obconic to short-campanulate, with gradually expanded hypanthium and calyx widening distally, 0.5-0.8 mm, pubescent proximally with straight to hooked hairs; sepals brown-purple, white to greenish at apex, sometimes proximally, veins absent, ± oblong, 0.5-0.7 mm, leathery to rigid, margins whitish to translucent, 0.1-0.2 mm wide, scarious, apex terminated by crest or mucro, hood broadly rounded, mucro rounded-triangular, ca. 0.1 mm, glabrous; staminodes absent or rudimentary; styles 2(-3), ca. 0.3 mm. Utricles ovoid or ellipsoid to subglobose, 0.4-0.5 mm, smooth, glabrous. The occasional occurrence of 3- or 4-merous flowers is unique to Paronychia chartacea among North American species of the genus.
Paronychia chartacea is in the Center for Plant Conservation's National Collection of Endangered Plants.
The following key is adapted from L. C. Anderson (1991).