Herbs perennial, rarely annual or biennial. Stem cespitose or simple. Leaves both basal and cauline, petiolate or not; leaf blade simple, entire, margin dentate or lobate; cauline leaves usually alternate, rarely opposite. Inflorescence a solitary flower or few- to many-flowered cyme, bracteate. Flowers usually bisexual, sometimes unisexual, actinomorphic, rarely zygomorphic; receptacle cyathiform or saucer-shaped. Sepals (4 or)5(or 7 or 8). Petals (4 or)5, yellow, orange, white, or red to purple, callose or not, distinctly veined, margin usually entire. Stamens (8 or)10; filaments subulate or clavate. Carpels 2, usually connate at least in placental region; ovary superior to inferior, usually 2-loculed; placentation usually axile; ovules many; integuments 1 or 2; nectary disc sometimes well developed, annular or semiannular. Fruit a 2-valved capsule. Seeds many.
About 450 species: Asia, Europe, North America, South America (Andes), mainly in alpine areas; 216 species (139 endemic) in China.
Two of the present authors (Gornall and Ohba) prefer to segregate Micranthes from Saxifraga on the basis of certain morphological differences (Webb & Gornall, Saxifrages of Europe, 1987) and data from DNA gene sequences (Soltis et al., Amer. J. Bot. 83: 371-382. 1996; and pers. comm.). However, for the purposes of this floristic treatment, Micranthes is treated as S. sect. Micranthes.
