See text Saxifragaceae is a family of herbaceous perennial flowering plants, within the core eudicot order Saxifragales.

The taxonomy of the family has been greatly revised and the scope much reduced in the era of molecular phylogenetic analysis.

Species are herbaceous perennials (rarely annual or biennial), sometimes succulent or xerophytic, often with perennating rhizomes.

Flowers have five to ten stamens, free and opposite the petals, with the anthers usually basifixed and opening by lengthwise slits.

The ovary is inferior to semi-inferior with two (sometimes three) carpels usually fused at the base, sometimes free, each topped with stylodium and capitate stigma.

[1][2] Saxifragaceae has long been considered in a pivotal position in the evolution of angiosperm lineage, located in an ancestral "Saxifragalean stock".

There, with three other subfamilies (Ribesoideaee, Iteoideae and Pterostemonoideae) it forms the Saxifragaceae alliance, while Penthoroideae and Tetracarpaeoideae are closely related within the core Saxifragales as shown in the cladogram.

[8][4][6] Peridiscaceae (4) Paeonia (Paeoniaceae) Liquidambar (Altingiaceae) Hamamelidaceae (27) Cercidiphyllum (Cercidiphyllaceae) Daphniphyllum (Daphniphyllaceae) Crassulaceae (34) Aphanopetalum (Aphanopetalaceae) Tetracarpaea (Tetracarpaeaceae) Penthorum (Penthoraceae) Haloragaceae s.s. (8) Iteaceae (including Pterostemonaceae) (2) Ribes (Grossulariaceae) Saxifragaceae s.s. (33) Numerous attempts have been made to subdivide Saxifragoideae (Saxifragaceae s.s.).

These have included dividing the family by the placentation of the ovules, as either parietal (e.g. Heuchera) or axile (e.g. Saxifraga).

[1][7] Molecular data indicate that the family can be considered as a number of informal clades, with two main lineages, saxifragoids and heucheroids and further subdivision of heucheroids into nine subclades or groups:[7][8][1] The clades and subclades are related as shown in the cladogram:[8] Saxifraga Leptarrhena Saniculiphyllum Boykinia Astilbe Heuchera Cascadia Darmera Peltoboykinia Micranthes Saxifragaceae s.s. has about 33–35 genera and about 640 species.