Rhizomes without tuberous thickenings or fleshy storage roots.  Stems 4-angled, 15-30 cm, pubescent in thin internodal line. Leaf blades lanceolate to lance-elliptic, 6-12 × 0.8-1.2 cm, margins often revolute, smooth or granular, sometimes papillate, sparsely ciliate proximately, glabrous or margins and midrib (adaxial) ciliolate. Inflorescences paired flowers (single by abortion) in distal 3-7 axils or in terminal cymes. Pedicels recurved to reflexed from base in fruit, with thin internodal line of pubescence. Flowers: sepals narrowly ovate to lanceolate, 6.5-7 × 1.5-2.5 mm, essentially glabrous or margins ciliolate in proximal 2; petals 8-9 × 1.5-2 mm, apex notch 0.8-1 mm deep, lobes narrowly rounded; anthers 5, yellow; styles 3.5-4 mm; stigmas adaxial, linear, 2.5-3 mm. Capsules 4-4.5 mm. Seeds 1-2, reddish brown, circular, plump, 2.5-2.6 mm; tubercles broadly conic to elongate, rounded, each with 8-12+ stipitate glands smaller than ca. 0.015 mm (50×). Flowering late spring, summer. Banks along peren-nial streams, often adjacent to coniferous forests; of conservation concern; 800-900(-1800?) m; Idaho. Pseudostellaria oxyphylla is known from Kootenai and Shoshone counties in northern Idaho.