Plants perennial; taproot stout; caudex much-branched, woody, producing many decumbent, leafy, short shoots and erect flowering shoots, often densely cespitose. Stems erect, decumbent at base, simple, branched in flowering region, slender, 10-20(-25) cm, sparsely pubescent and glandular. Leaves mostly basal; basal marcescent, densely tufted, long-petiolate, blade linear-oblanceolate, 1-3 cm × 0.5-3 mm, somewhat fleshy, setose-puberulent on both surfaces; cauline in 1-3 pairs proximal to inflorescence, reduced distally, blade linear, 1-4 cm × 0.5-2 mm. Inflorescences 1-3-flowered, with terminal flower, usually with 1 or 2 flowers at proximal nodes. Pedicels erect, sometimes slightly bent at apex, 4-2 times calyx, viscid glandular-puberulent, septa of hairs colorless. Flowers: calyx prominently 10-veined, narrowly campanulate, ± umbilicate, not contracted proximally around carpophore, 9-18(-22) × 3-6 mm, papery, glandular-puberulent, viscid, hairs with colorless septa, veins parallel, purple, with pale commissures, lobes with midrib present, triangular, 2-3 mm, margins purple tinged, membranous, often broadened distally into round, crenulate lobe; corolla off-white, usually pink or purple tinged, to 1 2 times longer than calyx, limb 2-lobed, 2-3 mm, sometimes with 2 small lateral teeth, appendages 2, ovate, 1-1.5 mm; stamens slightly longer than calyx; styles 3(-5), equaling petals. Capsules included in calyx, opening by 6 (or 8 or 10) ascending teeth; carpophore 1.5-3 mm, woolly. Seeds brown, reniform, ca. 1.5 mm, rugose on both surfaces, margins with large, inflated papillae. 2n = 48.

Flowering summer. Alpine grassy, gravelly, or rocky slopes and ridges, openings in subalpine forests, sagebrush, and on juniper slopes; 2400-3800 m; Calif., Idaho, Nev., Wash.

Silene sargentii is very similar to S. suksdorfii, but that species has purple-septate hairs on the calyx and pedicels, whereas those on S. sargentii are colorless (see M. A. T. Showers 1987). Also, the cauline leaves of S. suksdorfii are narrowly oblanceolate rather than linear, and the basal leaves are marcescent. Silene sargentii may be confused with S. bernardina and can intergrade with it in Nevada. However, that species is usually larger with a longer, tubular calyx and petals that are deeply divided into 4-6 narrow lobes, unlike S. sargentii, which has 2-lobed petals.