Plants perennial, rhizomatous or stoloniferous, not bulbiferous, rooting at nodes. Stems erect, 5-15 cm. Leaves alternate, secund, petiolate; blade linear, 2-40 × 0.5-2 mm. Inflorescences 1-bracteate; bract linear to oblanceolate, 10 × 2 mm. Flowers 1-12(-20); sepals 3.5-4.5 mm; petals 5, white with yellow blotches at base, or pinkish, 10-15 mm; stamens 5, anther yellow. Seeds 0.8-1.5 mm, tuberculate; elaiosome present.

Flowering early summer. Moist, often north-facing slopes of scree or alpine tundra; 0-1000 m; B.C., Yukon; Alaska.

Considered an ancestral species of Montia and Claytonia by some workers, M. bostockii appears related to M. vassilievii (Kuzeneva) McNeill of Asia and M. linearis of North America. The pollen is distinctly tholate with spiniferous saccae. The flowers of both M. bostockii and M. vassilievii closely resemble claytonias but have only three ovules, as opposed to arctic claytonias, which have six.