1. Therorhodion camtschaticum (Pallas) Small in N. L. Britton et al., N. Amer. Fl. 29: 45. 1914.
Rhododendron camtschaticum Pallas, Fl. Ross. 1(1): 48, plate 33 [as kamtschaticum]. 1784
Shrubs usually to 2 dm. Stems multicellular, eglandular-hairy (hairs unbranched), sometimes also stipitate-glandular-hairy, glabrate with age. Leaves often clustered toward distal portions of shoots; blade elliptic to obovate, 1-4.5(-6) × 0.7-2.4 cm, thin, margins ciliate (hairs eglandular), plane, apex rounded to obtuse or acute, mucronate, surfaces usually eglandular-hairy, sometimes sparsely glandular-hairy. Floral bud scales (and leaflike inflorescence bracts) eglandular-hairy, sometimes also stipitate-glandular-hairy. Inflorescences 2-3-flowered, sometimes flowers solitary; axis elongate. Pedicels 1-4.7 cm, eglandular- and/or stipitate-glandular-hairy; bracteoles 2, green, smaller than leaves. Flowers opening after shoot development, appearing to terminate leafy shoots due to their leaflike bracts; calyx lobes 8-21 mm, eglandular- and/or stipitate-glandular-hairy; corolla purple to, rarely, white, upper 3 lobes with darker spots, 19-32 mm, margins ciliolate, unicellular-hairy on outer surface, tube ± absent due to slit between lower 2 lobes, lobes 12-26 mm; stamens unicellular-hairy proximally. Capsules 6-11 mm, unicellular-hairy. 2n = 24, 26.
Flowering summer. Arctic and alpine tundra and heathlands, meadows, and subalpine woods; 0-1500 m; Alaska; e Asia (Japan, Russian Far East).
Therorhodion camtschaticum is found in the coastal and southern insular regions.