5. Douglasia idahoensis Douglass M. Henderson, Brittonia. 33: 52, fig. 1. 1981.
Idaho dwarf primrose Idaho dwarf primrose
Plants loosely cespitose mats with branched caudex. Stems prostrate to ascending, with terminal, green leaf rosettes. Leaves erect, reflexed in age, succulent; blade oblong to oblanceolate, 7-10 × 1-2 mm, margins entire, apex acute or obtuse, surfaces puberulent, glabrescent, hairs simple. Scapes 1-6 mm, elongating little in fruit, hairy, hairs simple and forked. Inflorescences 2-7-flowered, bracteate; bracts 5-9, lanceolate to ovate-lanceolate, 2.5-0.7 × 0.7-1.2 mm, with scattered, simple hairs. Pedicels 3-7 mm. Flowers: calyx 4-7 × 2 mm, with simple hairs; corolla pink to magenta with yellow throat, limb 10-12 mm diam., lobes 3-6 × 4 mm, margins emarginate or entire. 2n = 36.
Flowering mid summer. Gravelly soils, subalpine; 2000-3000 m; Idaho.
Douglasia idahoensis is known only from a narrow region of northern Idaho. Its fleshy leaves and multiflowered inflorescence are distinctive. Morphologically and geographically, it is closest to D. laevigata; molecular genetic analyses show a closer relationship to D. montana. The single chromosome count of n = 18 for this species is somewhat questionable because it represents an anomaly for the genus, which typically has a base number of 19; this count should be verified.