Plants perennial, producing several decumbent, short, woody, underground shoots bearing perennating buds and terminated by erect flowering shoots; taproot stout, woody; caudex crown branched. Stems simple but with short axillary leafy shoots, leafy, 40-60 cm, glossy, ± glabrous, with 10-20 nodes proximal to inflorescence. Leaves: basal withered at time of flowering; cauline whorled, appearing fasciculate (more than 4) at each node, connate at base, reduced distally, tapered at both ends, blade linear to very narrowly elliptic-lanceolate, 0.5-8 cm × 1-12 mm, base broadened, margins scabrous, apex acute, subglabrous to minutely puberulent on both surfaces. Inflorescences thyrsate, verticillate, open, with many short, ascending branches bearing large numbers of small, unisexual flowers, bracteate; bracts connate basally, triangular, 2-10 mm, margins finely ciliate, apex acuminate. Pedicels ascending, straight, fasciculate, wiry, ± equaling calyx, glabrous or sparsely and minutely puberulent. Flowers mostly unisexual; calyx pale green, indistinctly 10-veined, elliptic, constricted near base, umbilicate, ca. 5 × 2 mm, lobes with thickened midrib, ovate-obtuse, 0.2 mm, margins crenate, membranous; corolla greenish white, clawed, claw and limb not differentiated, narrowly oblong, unlobed, less than 2 times length of calyx, appendages absent; stamens exserted, longer than corolla; styles 3, exserted, longer than corolla. Capsules green, ovoid-conic, longer than calyx, opening by 6 teeth; carpophore shorter than 1 mm. Seeds brown, winged, reniform, ca. 1 mm, faces with shallow radiating ridges.

Flowering summer. Arable land, pastures, roadsides, sand dunes; 300-500 m; introduced; Sask.; Europe (Ukraine); Asia (Mongolia).

Silene sibirica is a very distinct species with masses of small flowers on stiffly erect stems, and narrow, fascicled leaves. It was abundant and persisted for a number of years in the 1950s near Duck Lake and Bladworth in central Saskatchewan.