Wildflowers of the United States

Home Journal Family Index - All States Photo Albums News About Privacy

Michaux's Saxifrage, Mountain Saxifrage - Micranthes petiolaris


Family: Saxifragaceae - Saxifrage family Genus Common Name: Saxifrage (Alpine Saxifrage) Native Status: NativeDicot Perennial Herb
Micranthes petiolaris - Michaux's Saxifrage, Mountain Saxifrage. Based on genetic studies the Saxifraga genus has been split up, with some species remaining in Saxifraga, one being classified in the monotypic genus Cascadia, and 47 species in the new genus Micranthes. There are only eight native North American Saxifraga species remaining in that genus, there are over forty in Micranthes. The easiest diagnostic for Micranthes vs Saxifraga is that the former has only basal leaves (or any cauline leaves may be crowded at the bottom of the stem,) while the latter (Saxifraga) will also have cauline leaves, although they may be very small.

Michaux’s Saxifrage, formerly Saxifraga michauxii, is now classified as Micranthes petiolaris (although there is a move afoot that may move it to Hydratica petiolaris.) While many authors still classify this as Saxifraga michauxii, I typically follow the ITIS classification when there is dispute or transition, so am including it as Micranthes petiolaris. I will continue to use Saxifrage as the genus common name so that Saxifraga and Micranthes species will be listed together in the lists ordered by common name, but ITIS lists Micranthes as Alpine Saxifrage.

Michaux’s Saxifrage is found on wet rocky places such as rock walls, boulder fields, and seeps in the Appalachian mountains from Maryland south to Georgia. The plants presented here were photographed on a rock wall along the Clingman’s Dome parking lot in the Great Smoky Mountains National Park.

Found in:
GA, KY, MD, NC, SC, TN, VA, WV

Leave comments on Micranthes petiolaris at this link.
Micranthes petiolaris

Distribution of Micranthes petiolaris in the United States and Canada:
USDA Plants Distribution Map temporarily unavailable.
Blue=Native; Grey=Introduced

Map from USDA Plants Database:
USDA, NRCS. 2017. The PLANTS Database (http://plants.usda.gov, 26 May 2017). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Search Our Database: Enter any portion of the Scientific, Common Name, or both.
Scientific name:
Common name:

Example: Enter "lob" in the common name field and you'll get all our species that have "lobelia" in the common name, as well as "sharp-lobed hepatica".

Do a general Google search of the entire site:



Follow on Twitter
Follow USWildflowers on Twitter










Site: Clingman’s Dome, GSMNP, Swain County, NC Date: 2013-September-23Photographer: Gerald C. Williamson
Nikon D7000
Tamron SP 90MM f/2.8 AF Macro
The blossom of Micranthes petiolaris has 5 white petals which are not necessarily equal in length. If these petals were leaves they would be considered petioled due to their narrow bases. The upper three petals have a pair of yellow marks on them; these marks are absent in the lower two petals. As with all Micranthes species, Michaux’s Saxifrage (aka Mountain Saxifrage) has 10 stamens.
Micranthes petiolaris

Site: Clingman’s Dome, GSMNP, Swain County, NC Date: 2013-September-23Photographer: Gerald C Williamson
Nikon D7000
Tamron SP 90MM f/2.8 AF Macro
Michaux’s Saxifrage can grow to about 18 inches tall. The flowers are in very open thyrses. I had not run across this term before, so here is a definition of thyrse from TheFreeDictionary: “A dense, paniclelike flower cluster, as of the lilac, in which the lateral branches terminate in cymes.”
Click on the photo for a larger image
Micranthes petiolaris

Site: Clingman’s Dome, GSMNP, Swain County, NC Date: 2013-September-23Photographer: Gerald C Williamson
Nikon D7000
The flowering stem rises from beside the basal leaves rather than from the center of the rosette.
Click on the photo for a larger image
Micranthes petiolaris

Site: Clingman’s Dome, GSMNP, Swain County, NC Date: 2013-September-23Photographer: Gerald C Williamson
Nikon D7000
The leaves of Micranthes petiolaris are on flattened petioles in a rosette. They are hairy, oblanceolate, and have large teeth.
Click on the photo for a larger image
Micranthes petiolaris

Site: Clingman’s Dome, GSMNP, Swain County, NC Date: 2013-September-23Photographer: Gerald C Williamson
Nikon D7000
The seeds of Mountain Saxifrage are about one-quarter inch long.
Click on the photo for a larger image
Micranthes petiolaris

References used for identification and information:

Commercial / Cookie Notice

Looking for Wildflowers for a specific state? Check here:



All content except USDA Plants Database map Copyright Gerald C. Williamson 2017
Photographs Copyright owned by the named photographer