Micranthes petiolaris (Raf.) Bush var. petiolaris

Locations ofMicranthes petiolaris (Raf.) Bush var. petiolaris in Virginia

Show image without county labels


Botanical Name
Micranthes petiolaris (Raf.) Bush var. petiolaris
Common Name
Michaux's Saxifrage, Cliff Saxifrage
Hydatica petiolaris (Raf.) Small; Saxifraga michauxii Britt.
Flora of Virginia Name/Status
Hydatica petiolaris (Rafinesque) Small
Long known as "Michaux's saxifrage", Saxifraga michauxii. Though reaching the northern limits of it range in Virginia and adjacent West Virginia, this S. Appalachian endemics is a frequent component of a wide variety of granitic, sandstone, and shaly cliffs and rock faces in our mountain counties.

Phylogenetic work has shown the genus Saxifraga, as traditionally circumscribed, to be polyphyletic. This species was briefly transferred to the genus Hydatica but, according to Flora of the Southeastern U.S., more recent work has demonstrated that it should be included in Micranthes. Two vars. are recognized, the Southern and Central Appalachian var. petiolaris (including our plants) and var. shealyi, a recently described taxon known only from Pickens Co., SC. The latter differs significantly from the nominate var. in being an annual (vs. perennial) and flowering in the spring (vs. flowering in the summer).
Crevices and ledges of exposed rock outcrops at middle to high elevations, not particular about rock type, occurring on quartzite, sandstone, granitic rocks, metabasalt, amphibolite, and other lithologies. Infrequent in the mountains, but locally occurring in large populations; rare in the inner Piedmont.
Native Status

To save this map, right-click (control-click for Mac users) on the map and choose "Save Image As...".