Vascular Plants of North Carolina
Account for False Pennyroyal - Trichostema brachiatum   L.
Members of Lamiaceae:
Members of Trichostema with account distribution info or public map:
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Section 6 » Order Lamiales » Family Lamiaceae
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DistributionFound only in a few places in the Mountains and northern Piedmont. Specimens documented for Granville, Orange (historical), and Madison counties. There are current and certainly valid sight records for Rockingham and Buncombe counties, and a long-historical one from Yancey County. Thus, currently present sparingly in the northern Piedmont and south to the central Mountains. Note that the species was not known from the state when RAB (1968) was published; the authors must have dismissed the very old report from Yancey County.

This is a wide-ranging species essentially to the north and west of NC. It ranges from New England to northern SC, to AL, and to TX.
AbundanceVery rare in the northern Piedmont and central Mountains. Certainly could occur in a few more sites in these two provinces, but even though a small plant, it probably is not being overlooked. It is a State Endangered species with a State Rank of S1.
HabitatThis species is restricted to quite high pH soil, only over mafic or calcareous rocks, such as diabase, limestone, or other calcareous material. It favors dry, often rocky sites, or at least where the soil is very thin and at times a bit gravelly. Communities in NC include Diabase Barrens, Dry Calcareous Cliffs, and Mafic Cliffs.
See also Habitat Account for Basic Barrens and Glades
PhenologyBlooms in August and September, and fruits shortly after flowering.
IdentificationThis is a quite small species that would easily be overlooked by the general public, though a careful botanist/biologist working in dry and high pH soil might not. It has several branches (usually), but even so grows only to about 9 inches tall, rarely 1-foot tall. It has numerous opposite leaves, each elliptical and about 1-inch long and half as wide, tapered at the base and tip. It is nearly sessile, is practically entire on the margins, and has 3 prominent veins. Many of the leaf axils, mostly in the upper portions, have one to several tiny blue flowers, each with 5 petals nearly symmetrical (and thus not looking like a mint), but only about 1/6-inch across. It looks nothing like the other three Trichostema species in the state, leaving one to wonder why it was moved into this distinctly different genus. The species will likely be quite difficult to identify when not in bloom, as the elliptical leaves and small stature of the plant do not catch attention; but, if the blue flower color is seen on a plant, then a close look is warranted.
Taxonomic CommentsThis species was formerly placed in the genus Isanthus, named as I. brachiatus.

Other Common Name(s)Glade Bluecurls, Pennyroyal Bluecurls, Fluxweed
State RankS1
Global RankG5
State StatusE
US Status
County Map - click on a county to view source of record.
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B.A. SorriePhoto taken 1982, Dinosaur Footprints by Connecticut River, Holyoke, MA. Photo_non_NCPhoto_non_NC

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