Saxifraga is the largest genus in the family Saxifragaceae, containing about 440 species of holarctic perennial plants, known as saxifrages[2] or rockfoils.[3] The Latin word saxifraga means literally "stone-breaker", from Latin saxum ("rock" or "stone") + frangere ("to break"). It is usually thought to indicate a medicinal use for treatment of urinary calculi (known as kidney or bladder stones), rather than breaking rocks apart.[2][4]
Most saxifrages are small perennial, biennial (e.g. S. adscendens) or annual (e.g. S. tridactylites) herbaceous plants whose basal or cauline leaves grow close to the ground, often in a rosette. The leaves typically have a more or less incised margin; they may be succulent, needle-like and/or hairy, reducing evaporation.[5][6][7]
The inflorescence or single flower clusters rise above the main plant body on naked stalks. The small actinomorphic hermaphrodite flowers have five petals and sepals and are usually white, but red to yellow in some species. Stamens, usually 10, rarely 8, insert at the junction of the floral tube and ovary wall, with filaments subulate or clavate. As in other primitive eudicots, some of the 5 or 10 stamens may appear petal-like.[citation needed] and it lives in tundral ecosystems.[5][8][6]
A genus of about 440 species. The former monotypic genus Saxifragella has been submersed within Saxifraga, the largest genus in Saxifragaceae, as Saxifraga bicuspidata.[9][5] Also the genus Saxifragopsis (strawberry saxifrage) was previously included in Saxifraga.[1]
Based on morphological criteria, up to 15 sections were recognised.[10] Subsequent molecular phylogenetic studies reduced this to 13 sections with 9 subsections. The former sections Micranthes and Merkianae are more closely related to the Boykinia and Heuchera clades.[11] Modern floras separate these groups as the genus Micranthes.[12][6]
Plants formerly placed in Saxifraga are mainly but not exclusively Saxifragaceae. They include:[citation needed]