Vascular Plants of North Carolina
Account for Mapleleaf Alumroot - Heuchera aceroides   Rydberg
Members of Heuchera with account distribution info or public map:
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Section 6 » Family Saxifragaceae
AuthorRydberg
DistributionSome references consider this taxon as H. longiflora var. aceroides, but some references have split it off as a good species. This website follows Weakley (2018) in considering it as a valid species. It is restricted mostly to calcareous cliff areas in the central to southern mountains; known only from four counties -- Madison, Buncombe, Haywood, and Jackson. The great majority of the specimens and locations are from Madison County.

This is a southern Appalachian endemic, occurring only in western NC and eastern TN.
AbundanceUncommon to locally common along the French Broad River in Madison County; rare and local elsewhere in the range. The NCNHP only considers it as a Watch List species, despite its small range, though with a W7 (poorly known) rather than W1 (rare but relatively secure) status. The S2 rank is probably accurate, considering the quite large number of records from Madison County. Because NatureServe does not consider this taxon as valid, the website editors are providing a proposed Global Rank of G2?, adding the Q to indicate a questionable taxon.
HabitatThis species is restricted in habitat, mainly found on limestone/calcareous cliffs and on lightly vegetated dry slopes over that rock. It can rarely be found on mafic cliffs that are not calcareous.
See also Habitat Account for Montane Calcareous Barrens and Woodlands
PhenologyBlooms in May and June, and fruits shortly after flowering.
IdentificationThe seven species of Heuchera in NC are nearly all quite similar to each other, and some require detailed keys to separate. Most, including this species, have a cluster of several large basal leaves and an essentially long but naked stem that contains the inflorescence. In this species, the long petioles are essentially smooth, and the fairly large leaf blade is also smooth. The blade is like most others, being generally rounded in shape but with a cordate base, and several small lobes on a very serrated margin. The leaves are usually mottled in color, being dark green along and near the veins and silvery or pale green on the rest of the upper leaf surface. The inflorescence is held well above the leaves and is 6-12 inches tall, with scattered flowers close to the scape. The flowers are generally held horizontally, the bracts are herbaceous, and styles are inserted -- generally shorter than the calyx. The stamens are also shorter than the calyx. Some of these flower characters are too technical for most people, and thus check Weakley (2018) or other references for keys. In general, this is the primary (if not only) Heuchera species that grows on the dry slopes and outcrops along the French Broad River in Madison and extreme northern Buncombe County, with strongly mottled leaves and reproductive parts not extending beyond the petals/sepals. Also, the leaves and petioles tend to be smooth or essentially so.
Taxonomic CommentsSee Distribution. NatureServe does not even consider this a valid taxon; instead it just treats it within the full species H. longiflora.

Other Common Name(s)Longflower Alumroot (the common name for H. longiflora)
State RankS2
Global RankGNA [G2?Q]
State StatusW7
US Status
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