Vascular Plants of North Carolina
Account for Hartwig's Locust - Robinia hartwigii   Koehne
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AuthorKoehne
DistributionA tiny range in the Highlands, NC, area – known for certain only (as native populations) in Macon and Jackson counties; reported from Mitchell County (likely not native there). Most populations are limited to Whiteside and Satulah mountains and The Fodderstacks.

This species has recently been proven to be a valid one, via genetic work by Brandon Wheeler (2023 Rare Plant Discussion Group). It is limited to extreme southwestern NC.
AbundanceRare in the southeastern portion of Macon County and adjacent southern Jackson County, but can be locally numerous on some granitic domes there. Essentially absent elsewhere. The NCNHP tracks it as Significantly Rare and likely will give it a high rank in the near future.
HabitatIn NC it is strictly limited to the margins of granitic domes and in adjacent woods on such exposed domes, in thin soil, generally in full sun or partial shade.
PhenologyBlooms in June and July; fruits in August and September.
IdentificationThis is a deciduous shrub that grows to 9-12 feet tall. As with other locusts, it has numerous (13-23) leaflets. It has pink to rosy colored flowers, usually richer colored than the quite similar Clammy Locust (Robinia viscosa). This species has pubescent and somewhat glandular twigs and inflorescences, but so does Clammy Locust, which tends to be even “stickier” and usually has paler light pink flowers. Needless to say, these two species can be difficult to separate from each other; you may need technical keys. Many references consider this species as a part of R. viscosa.
Taxonomic CommentsThis taxon has a number of issues. First, the scientific name is often written as R. hartwegii, though Weakley (2018) makes it clear that this name is incorrect, as the initial publication in 1913 listed it as Robinia hartwigii, and it must stand as that. However, it is not clear from references whether the person whom the plant is named was Hartweg or Hartwig; most references suggest that Hartweg is the better common name, but this website is using Hartwig to be in line with the scientific name of hartwigii. More importantly, many references consider this taxon within R. viscosa, as R. viscosa var. hartwigii or R. viscosa var. hartwegii.

Other Common Name(s)Hartweg’s Locust
State RankS1S2
Global RankG3T2 [G2]
State StatusSR-L
US Status
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