Brook saxifrage has recently been reclassified as Saxifraga odontoloma from S. arguta..
Brook saxifrage is a perennial with a single, erect stem from 20-60 cm high arising from a cluster of basal leaves atop well-developed horizontal rootstocks. The herbage is smooth-surfaced below and somewhat glandular-hairy above, the hairs being tipped with red, purple or yellowish glands. The leaf blades are kidney-shaped with many (15-29) rounded to pointed teeth around the margins. They are 2-8 cm wide and about 2/3 as long.
The inflorescence is found atop the bare stem. It consists of open, cymose panicles with the branches spreading and rising. The calyx is cleft almost its entire length of 1.5-2 mm. The 5 calyx lobes are oblong-ovate or oblong-lanceolate. The 5 white petals are each orbicular in shape and spreading, from 3-4 mm long. The petals may all be equal in size, or 2-3 may be larger than the other 2 (This a difference from Saxifraga punctata.). The 5 white stamens are about equal in length to the petals. The ovary is superior with 2 (up to 4) carpels which are fused 1/3-3/5 of their length. The ovary is red to purple.
Brook saxifrage may be found in wet meadows and along streams or springs at higher elevations.
Brook saxifrage may be found from southern Alaska south through British Columbia to the Cascade and Olympic Mts. of Washington and Oregon and the Sierra Nevada of California to southern California. It may be found east to Alberta and south through the mountains of Idaho, Montana, northeastern Oregon and in the Rocky Mts. south to Arizona and Mew Mexico.
