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False Pennyroyal, Fluxweed, Glade Bluecurls - Isanthus brachiatus


Family: Lamiaceae - Mint family Genus Common Name: Fluxweed Native Status: NativeDicot Annual Herb
Isanthus brachiatus - False Pennyroyal, Fluxweed, Glade Bluecurls. This is one of many plants undergoing changes in classification. According to my research, it was originally considered to be part of Trichostema (Linnaeus, 1737), subsequently became the sole member of the Isanthus genus (Michaux, 1803), in 1978 was sent over to Trichostema for a while (Lewis), and recently some authorities have moved it back to Isanthus as the only species in that genus. Of course, during all of this scientific debate, those of us classified as commoners would have continued to call it whatever we called it previously be it False Pennyroyal or Fluxweed, or whatever other common name was applied locally. The Trichostema genus members are commonly known as Bluecurls.

False Pennyroyal is listed as Special Concern, Endangered, or Threatened in Connecticut, Massachusetts, Michigan, and New Jersey. It is rare in the remaining New England states where it can be found at all.

This plant was pointed out and identified for me by Jay Clark, author of Wildflowers of Pigeon Mountain on a walk through a cedar glade at the foot of Pigeon Mountain in Walker County, Ga in late September.

Found in:
AL, AR, AZ, CT, DC, FL, GA, IA, IL, IN, KS, KY, LA, MA, MD, MI, MN, MO, MS, NC, NE, NJ, NM, NY, OH, OK, PA, SC, SD, TN, TX, VA, VT, WI, WV

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Isanthus brachiatus

Distribution of Isanthus brachiatus in the United States and Canada:
USDA Plants Distribution Map temporarily unavailable.
Blue=Native; Grey=Introduced

Map from USDA Plants Database:
USDA, NRCS. 2017. The PLANTS Database (http://plants.usda.gov, 16 Dec 2017). National Plant Data Team, Greensboro, NC 27401-4901 USA.

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Site: Blue Hole Area, Pigeon Mountain, Walker County, GA Date: 2011-September-24Photographer: Gerald C. Williamson
Nikon D7000
Tamron SP 90MM f/2.8 AF Macro
There are typically 1 to 3 lavender to blue 5-petaled blossoms arising from the leaf axils on pedicels that are about inch long. The blossoms are about a quarter of an inch long.
Isanthus brachiatus

Site: Blue Hole Area, Pigeon Mountain, Walker County, GA Date: 2011-September-24Photographer: Gerald C Williamson
Nikon D7000
False Pennyroyal is branching and moderately leafy. It grows to a height of about 1.5 feet.
Click on the photo for a larger image
Isanthus brachiatus

Site: Blue Hole Area, Pigeon Mountain, Walker County, GA Date: 2011-September-24Photographer: Gerald C Williamson
Nikon D7000
The calyx of Isanthus brachiatus has 5 pointed lobes and is edged with short hairs, and on this specimen is covered with glandular hairs. This leaf is has short hairs on the edges and appear to be covered with glandualr hairs or resin dots. A close look at the stem shows a similar pattern.
Click on the photo for a larger image
Isanthus brachiatus

References used for identification and information:

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All content except USDA Plants Database map Copyright Gerald C. Williamson 2017
Photographs Copyright owned by the named photographer