Vascular Plants of North Carolina
Account for Torrey's Mountain-mint - Pycnanthemum torreyi   Bentham
Members of Lamiaceae:
Members of Pycnanthemum with account distribution info or public map:
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DistributionScattered over the Mountains, western Piedmont, and the northeastern Piedmont; probably present in the intervening north-central parts of the Piedmont, though there may well be geologic reasons (scarcity of suitable high pH soils?) in this last region that make it hard to find.

This is a globally rare species ranging from CT and western PA south to central NC and barely to northeastern GA, as well as to AR.
AbundanceRare to perhaps locally uncommon, in at least parts of the Mountains, western Piedmont, and northeastern Piedmont. Certainly overlooked or under-collected. The NCNHP lists it as Significantly Rare, but with a State Rank of S1. Certainly, with collections from at least 10 counties and additional reports for 3 others, a State Rank of S2 is more appropriate. And, the species certainly is not as rare over its range as the NatureServe's G2. It should be G3, or G3?.
HabitatThis is a species of high pH soil, generally in dry to mesic conditions. It grows in rocky woods, openings in upland woods, wooded borders, or powerline clearings, but over rocks such as amphibolite, gabbro, or limestone. As this species has been recently split out from P. verticillatum, some details of habitat are not fully understood.
PhenologyBlooms from June to October, and fruits shortly after flowering.
IdentificationThis species is a typical mountain-mint, being about 3 feet tall, freely branched in the upper portions of the stem, and with numerous pairs of opposite leaves. The stem of this species is quite hairy on both the edges and the sides, a key identification character; the very similar P. verticillatum has canescent (white) hairs on the stem and branches, making them look whitish in color. In this species, the leaves tend to be lanceolate, narrower than many species in the genus, about 1.5-2 inches long and about 8-12 mm (2/5-inch) wide, about 4-5 times longer than wide, and nearly sessile, barely toothed along the margin. These species have rather flat-topped heads of about 1-2 inches wide at the ends of each branch, subtended by bracts, with the flowers being very small and generally white with some purple spots on the lower lip. There are many such heads in bloom over the plant, often dozens of them. This species can also be separated from P. verticillatum by having the bracts of the inflorescence and upper surface of the leaves glabrous or only slightly pubescent, as opposed to canescent (whitened) on the upper surfaces in that species. Also, this species is apparently limited to high pH soil, in case you can determine the soil chemistry (by other vegetation, for example). P. virginianum, also a high pH soil species, has more slender leaves (usually under 8-10 mm wide), but is only somewhat hairy on the stem edges and occasionally the sides. This mountain-mint may not be quite as rare as NatureServe and NCNHP seem to indicate, and certainly more counties in the state can be found for it.
Taxonomic CommentsRAB (1968) and some other older references included it within P. verticillatum. An alternate spelling is torrei.

Other Common Name(s)None
State RankS1 [S2]
Global RankG2
State StatusSR-T
US Status
County Map - click on a county to view source of record.
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B.A. Sorriesame data OrangePhoto_natural
B.A. SorrieOrange County, 2001, Duke Forest roadside. OrangePhoto_natural
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