Vascular Plants of North Carolina
Account for Swamp Saxifrage - Micranthes pensylvanica   (L.) Haworth
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(L.) Haworth
DistributionCurrently known only from the northern Mountains, limited to a few sites in Watauga County. In 1986, a colony was discovered in northern Wake County; it was later that year seen by one of the website authors (LeGrand), but the habitat has been strongly degraded in that highly developed county, and the population has not been found again.

As would be expected, this is a Northern species, ranging from ME and central Canada south to northern NC and eastern MO. It is known from just one county in TN and two in NC. However, it does occur at scattered sites in the central VA Piedmont, and thus its occurrence in Wake County is not overly unprecedented.
AbundanceVery rare in the northern Mountains, and in a very limited habitat. Not surprisingly, this is a State Endangered species, with a State Rank of S1.
HabitatThis is a species of bogs, wet swampy places, wet meadows, and forested or lightly-wooded seepages. Though it grows best over calcareous or mafic rocks (circumneutral soils) in its range, there is no evidence of this association in NC. The few current sites in Watauga County are in bogs.
PhenologyBlooms from April to June, and fruits shortly after flowering.
IdentificationThis species is easily identified by its basal leaves, as is M. micranthidifolia. In M. pensylvanica, each of the many basal leaves is very long and entire (or with small serrations not visible at much distance), mainly oblanceolate, about 8-10 inches long and about 2.5 inches wide. These leaves tend to be strongly ascending, a good field character. From the center of the plant grows the very thick and robust flowering stalk, with the flowers starting to bloom when the stalk is about 1-2 feet tall, but in full flower this stalk can reach 3 feet high or more. Thus, in early bloom the inflorescence is compact, with flowers close to the stem, but by late bloom the panicle is broader and taller. The petals are greenish white and not overly striking at a distance. It is the larger cluster of "tobacco-like" leaves, which also resemble narrow leaves of Skunk Cabbage (Symplocarpus foetidus), that is obvious when first seen. This species does grow in at least one protected site in NC, but for the most part, if you want to see this robust bog species, you will need to look for it north of NC.
Taxonomic CommentsAll NC species of Micranthes were formerly included in the genus Saxifraga.

Other Common Name(s)Eastern Swamp Saxifrage
State RankS1
Global RankG5
State StatusE
US Status
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