Vascular Plants of North Carolina
Account for Carolina Saxifrage - Micranthes caroliniana   (A. Gray) Small
Members of Saxifragaceae:
Members of Micranthes with account distribution info or public map:
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Section 6 » Family Saxifragaceae
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Author(A. Gray) Small
DistributionRestricted to the northern Mountains, south to Yancey and Burke counties, though most records are for Ashe County. Note that the website editors have decided that specimen records from farther south (e.g., Swain Co.) are likely misidentified specimens of M. careyana, as Weakley (2018) says that M. caroliniana occurs in NC only in the northwestern counties.

This is a Southern Appalachian endemic, ranging just from southwestern VA south to northwestern NC and northeastern TN. The BONAP map is incorrect and includes many records considered to be M. careyana.
AbundanceUncommon to infrequent in Ashe County, but rare to uncommon east to Alleghany County and south to Yancey and Burke counties. The NCNHP considers this as a Significantly Rare species. However, its S3 State Rank is too liberal, as their database barely has 20 records, with a few of these as historical. As many are of high quality and are on protected lands, the website editors suggest S2S3 instead of S2 for the rank.
HabitatThis species has essentially identical habitats as that of M. careyana. It is found mostly on shaded, cool rock crevices and ledges, usually where moist or wet. The rock type is not essential, as it can be found on both mafic and felsic rock types.
See also Habitat Account for Montane Mesic Rock Faces and Crevices
PhenologyBlooms in May and June, and fruits shortly after flowering.
IdentificationThis species and most others in the genus have a cluster of basal leaves with short petioles. The leaf blade is ovate or rounded, about 1.5 inches across and wide, with many scalloped edges or low rounded teeth; the base is somewhat tapered to the petiole. The leaves of M. careyana, as well as the habitat, are very similar, as are the inflorescences. Each has a flowering stalk about 9-10 inches tall, with a large panicle of medium-sized white flowers (for the size of the plant). Each flower has 5 white petals, with the spread flower about 1/4-inch across. In M. caroliniana, the 5 sepals start out spreading but later become reflexed (swept back); in M. careyana, the sepals are at first erect and then spreading. Also, in M. caroliniana the filaments are slightly clavate (club-like), whereas in M. careyana the filaments are filiform (extremely narrow); Weakley (2018) mentions to "use 10x" hand lens! M. careyana is the more often found of the pair from the central mountains southward, where M. caroliniana does not occur. To see these, scrutinize rocks carefully, especially ones in shaded places and particularly where damp.
Taxonomic CommentsAll of the NC Saxifraga species have been moved into the genus Micranthes in recent years. There has been much confusion about the identities of many specimens of this species and M. careyana over the years, though both have long been considered as good and separate species.

Other Common Name(s)None
State RankS3 [S2S3]
Global RankG3
State StatusSR-T
US Status
USACE-empFACW link
County Map - click on a county to view source of record.
Photo Gallery
B.A. SorrieThree Top Mountain, 1990s. AshePhoto_natural

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