Japan Flora: Shrub; young branches slightly angled, pubescent on upper portion; leaves rather thinly chartaceous, lanceolate to broadly lanceolate, 3-10 cm. long, 1-3 cm. wide, acuminate to acute, usually acutely duplicate-toothed, slightly pubescent on upper side while young, the petioles 1-3 mm. long; inflorescence terminal, densely many-flowered, 7-15 cm. long, short-pubescent; flowers pink, 5-7 mm. across; calyx pubescent, the teeth deltoid, acute, erect; stamens much longer than the petals; ovary glabrous. July-Sept. Wet boggy places in mountains.
Hokkaido, Honshu (n. and centr. distr.). Distributed throughout the cold regions of the Old World.
Korea Flora: Deciduous shrub, 1-1.5m tall. Winter buds narrowly ovoid, apex acute (2-3mm long), with 5-8 basal scales; branches angular, pubescent or glabrous. Leaf scars semicircular. Leaves alternate, narrowly elliptic, 4-8cm × 1-2cm; glabrous on the upper surface, sparsely pubescent beneath, margins finely serrate. Petioles under 1mm long, nearly absent. Inflorescences large, terminal panicles, 5-8cm in diameter; peduncles and pedicels densely pubescent. Calyx tube obconic, divided into 5 lobes, ovate-acuminate, nearly glabrous. Petals pale pink, obovate-orbicular; stamens longer than petals, red, filaments glabrous, anthers yellow. Ovaries 4-7. Fruits follicles, pubescent along the inner vascular bundles.
Chromosome number: 16, 36. Flowering: Late May to mid-September. Fruiting: Late September to mid-October. Distribution: Northeastern China, northeastern Far East Russia (including southern Kuril Islands), Hokkaido to central Honshu (Japan); Hamgyeongbukdo to southern Gangwon , Gyeonggi , and parts of Hwanghae (Korea).