Description from Flora of China
Shrubs evergreen, dwarf. Stems procumbent or ascending. Leaves decussate, sessile, appressed and crowded, imbricate, usually 4-ranked. Leaf blade small, entire or fimbriate-ciliate, veinless, 1-channeled on back, sometimes plane or convex. Flowers solitary, axillary, pendulous. Pedicel slender, base bracteate; bracteoles absent. Flowers usually 5-merous. Calyx lobes imbricate, subfree. Corolla white or pink, campanulate, lobed or cleft; lobes recurved. Stamens included; filaments straight, flattened; anthers ovate, with two long recurved awns. Ovary superior, glabrous, with many ovules per locule. Capsule depressed-globose, each valve 2-cleft at apex. Seeds many, minute, wingless.
About 17 species: circumboreal, extending south into China, the Himalayan region, Japan, Russia, and W North America; 11 species (six endemic) in China.
(Authors: Fang Ruizheng (方瑞征 Fang Rhui-cheng); Peter F. Stevens)