Common Western Saxifrage, Northwestern Saxifrage, Wholeleaf Saxifrage: Micranthes integrifolia (Synonyms: Saxifraga integrifolia, Saxifraga integrifolia var. integrifolia)

Northwestern saxifrage is a perennial with a single stout, erect stem, from 10-30 cm high arising from a cluster of basal leaves. The stems and leaves are typically covered with gland-tipped hairs, especially within the inflorescence. The stems lack leaves and are unbranched (except as part of the inflorescence). The leaf blades narrowly rhombic to ovate-lanceolate, narrowed gradually to broad petioles equal to or usually shorter than the blades. The thick blade is usually 2-4 cm in length, but may occasionally reach as long as 12 cm. The width ranges from 1-2 cm wide but on occasion, may be as much as 6 cm. The leaf margins are usually entire, but occasionally may be lightly toothed.

The inflorescence is a cymose-panicle consisting of several short branches, the lowest ascending and the longest (See photo at right.). The calyx is top-shaped with each of the 5 reflexed lobes about 2 mm long. The 5 petals may be white, yellowish, or greenish-white, or they may be absent. They range from 1.5-3 mm long and are narrowly obovate in shape. The carpels are separated nearly to their base with the short styles abruptly diverging.

Northwestern saxifrage at one time consisted of 5 separate varieties. Currently, only variety integrifolia remains as a member of this species. The other 4 varieties have been split from S. integrifolia and grouped to form the following 2 species.

Petalless Saxifrage Saxifraga apetala (S. integrifolia var. apetala): Leaves entirely basal, rhombic-lanceolate in shape, narrowed gradually to the wide, ciliate-pilose petioles. The inflorescence is very congested and capitate. The petals are lacking or very much reduced, yellowish or greenish-white if present. Found east of the Cascade Mts. from Okanogan County south to Yakima County in Washington and in the Steens Mt. in southeastern Oregon.

Swamp Saxifrage Saxifraga nidifica var. claytoniifolia (S. integrifolia var. claytoniaefolia): The leaves are all basal, the blades broad and abruptly narrowed to the petiole (which is often as long as the blade), the margins generally entire. The petals are white and generally longer than the sepals. Found east of the Cascade Mts. from Okanogan County in Washington south to southern Oregon and east to southeastern Washington, northeastern Oregon, and western Idaho. Also found west in the Columbia River Gorge to the Willamette Valley of northwestern Oregon.

Swamp Saxifrage Saxifraga nidifica var. nidifica (S. integrifolia var. columbiana & var. leptopetala): Leaves all basal with entire margins, the blades rhombic-ovate in shape, narrowed to slender, weakly ciliate or glabrous petioles. . Inflorescence is a cyme with 3-9 branches. The petals are white to greenish-white, up to 2 mm long, and generally shorter than the sepals. Found in the Blue and Wallowa Mts of northeastern Oregon and southeastern Washington, central and southwestern Idaho, and south through southeastern Oregon to northern Nevada and northeastern California.

Northwestern saxifrage may be found on prairies, grassy slopes, and meadows which are seasonally moist in the spring but dry in the summer.

Northwestern saxifrage is found west of the Cascade Mts from British Columbia south to Lincoln County OR, and east along the Columbia River Gorge to Wasco County, OR.

Close-ups of northwestern saxifrage as seen in moist cracks on rock outcrops above the John Day River along Oregon Highway 19 at milepost 80 in central Oregon..........April 8, 2007. The photo at left shows a cluster of white flowers. In the center photo, note that the individual petals are somewhat rounded or obovate in outline. Note that one of the flowers of the upper cluster has formed reddish bulbils or propagules, a form of asexual reproduction common with some members of this family. The photo at right shows the bluish, tubular flowers of naked broomrape (Orobanche uniflora) which is a common parasite of northwestern saxifrage. In the lower photo, note the marginal hairs along the upper leaf edge.

Additional close-up photos of northwestern saxifrage as seen in a moist ditch along Forest Road #1647 in southeastern Logan Valley, Malheur National Forest.........June 3, 2011. Note that the petals are a clear white (not creamy with hints of yellow) and ovate in shape. The stems are covered with numerous gland-tipped hairs, while the leaf blades are also covered with minute hairs. The inflorescences here mostly appear tightly capitate with some short branches on some, but plants were present with several longer, more open panicles.

Northwestern saxifrage as seen at the edges of vernally moist pools at the junction of Miller Ranch Road and the Sprague Highway on BLM land at the Fishtrap Lake unit, eastern Washington...........April 28, 2014.

Northwestern saxifrage observed in a drainage dropping south from Box Canyon Road towards Rock Canyon, near the southern boundary of the Simcoe Mountains Unit of the Klickitat Wildlife Area.....April 15, 2021.

These photos show the leaves (and an elongating inflorescence at upper right) of northwestern saxifrage as seen on moist cliffs along the Deschutes River several miles downstream from the Sherar's Bridge.........March 24, 2007. Note the shape of the blades which are generally much longer than wide, usually not triangular-shaped and have bases which tend to grade into the broad petiole more gradually than the similar swamp saxifrage Saxifraga nidifica var. claytoniifolia.