Plants 0.2-1.6 dm. Stems erect to ascending. Leaves 3-18 mm; proximal cauline whorled, blade linear-spatulate; distal usually opposite, blade broadly linear; petiole to 10 mm; margins entire. Inflorescences: peduncle 2-8 cm. Flowers: receptacle shorter than broad, expanded into small ring beneath calyx; petals white, alternately obovate and oblanceolate, 1-5 × 1-3 mm, apex rounded; stamens 4-6, in 1 series; filaments ± equal, usually as broad as anthers; anthers ovoid, minute, much shorter than filaments. Capsules to 25 × 1.5 mm. 2 n = 16.

Flowering early-late spring. Sandy bluffs, meadows and partly sunny, moist banks; of conservation concern; 0-300 m; B.C.; Calif., Oreg., Wash.

Flowers of Meconella oregana often display irregularities such as fusion, loss, or addition of parts (W. R. Ernst 1962). Some specimens from central California (Alameda and Contra Costa counties) are difficult to assign with certainty to either M . oregana or M . californica . Depauperate plants of the latter species sometimes can be distinguished from M . oregana only by their unequal and more numerous stamens (W. R. Ernst 1967).