Vascular Plants of North Carolina
Account for Loomis's Mountain-mint - Pycnanthemum loomisii   Nuttall
Members of Lamiaceae:
Members of Pycnanthemum with account distribution info or public map:
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Section 6 » Order Lamiales » Family Lamiaceae
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DistributionBased on NCU specimens in the SERNEC database, this species ranges over essentially all of the Piedmont, and over the central and southern mountains, perhaps being absent in the northern half of them. Ranges sparingly into the northern half of the Coastal Plain. There is much confusion of the ranges of this species, P. incanum, and P. pycnanthemoides in the state, as all had been lumped into P. incanum by RAB (1968), even though most references have the last two as good species. For example, A 2017 specimen collected in Brunswick County is labelled as P. pycnanthemoides, but is in SERNEC as P. loomisii.

This is a Southern species, ranging from VA west to southern IL, and south to northern FL.
AbundanceThough scarce in VA and KY northward, it appears to be a common species in TN and NC, contra Weakley's (2018) map. Though his map shows it as "rare" in all three NC provinces in NC, the specimen data from NCU (and many other herbaria not included on the website range map) show otherwise. Based on such information, the species appears to be fairly common to perhaps frequent in the Piedmont and southern mountains, but very rare in the Coastal Plain. It might well be more numerous in NC than is P. pycnanthemoides, but this is not clear at the present time. As NatureServe gives a Global Rank of G4?, the website editors give a State Rank of S4?
HabitatThe habitats appear to be very similar to those of P. incanum and P. pycnanthemoides -- open, upland woods, wooded borders, and other dry sites in partial shade.
PhenologyBlooms from late June to August, and fruits in September and October.
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 leaves tend to be ovate, nearly sessile, toothed along the margin, and about 2-3 inches long and half as wide. These species have rather flat-topped heads of about 1-2 inches wide at the ends of each branch, subtended by whitened 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. Separation of this species from others is technical and involves closely examining the calyx or the seeds. Use Weakley (2018) to key out the species. This species likely will have to be distinguished from the very similar P. incanum and P. pycnanthemoides by seed characters; this species has smooth nutlets, as opposed to rough or pitted on others. This species should be encountered from time to time by biologists, probably less so than the very similar P. pycnanthemoides in the mountains, but possibly more often than that species in the Piedmont, not to mention encountering P. incanum as well! You will likely need to collect seeds to be sure.
Taxonomic CommentsAs mentioned above, this species has often been included within P. incanum, and many references probably still do. Thankfully, there are no named varieties for it.

Other Common Name(s)None
State Rank[S4?]
Global RankG4?
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US Status
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Pat MomichMadison County; 31 August 2020; seeds are smooth MadisonPhoto_natural
Pat MomichMadison County; 31 August 2020
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