Glabrous annual, mat-forming herb. Stems branched at the base, prostrate, to 20 cm long. Leaves of basal rosette spatulate, to 25 mm long; cauline leaves 4 to 6 per node, 5–15 mm long, narrowly oblanceolate with entire margins. Flowers several in axillary umbels with pedicels 3–8 mm long; sepals 5, separate, white-margined, 2 mm long, oblong, 3-nerved; petals absent; stamens 3; pistil 1 with 3 styles and a superior ovary. Fruit a many-seeded, ovoid capsule ca. 2 mm long (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).