Description from Flora of China
Herbs, annual or perennial, caudices of latter thick, lignified, covered with numerous scales, usually branched, stems thus caespitose. Leaves alternate, but sometimes 4 or 5 leaves aggregated below pedicel, appearing whorl-like. Flowers solitary, terminal on main stems and branches, rarely in a dichasium and dichasia aggregated on top of stem and branches, pedicellate. Calyx tubular or tubular-campanulate, 5- or rarely 4-lobed. Corolla tubular-campanulate, (3-)5-lobed. Stamens 5, often aggregated and surrounding ovary at upper part. Ovary superior, conical, mostly 5-locular, less frequently 4- or 3-locular. Fruit a capsule, loculicidal. Seeds numerous, brown-red or brown-black.
Eighteen species: Himalaya and the Hengduan Mountains; 17 species (nine endemic) in China.
(Authors: Hong Deyuan (洪德元); Thomas G. Lammers, Laura L. Klein)