Pycnanthemum flexuosum

From Coastal Plain Plants Wiki
Jump to: navigation, search
Pycnanthemum flexuosum
Pycn flex.jpg
Photo taken and permission granted by Jeff Pippen,
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta – Flowering plants
Class: Magnoliopsida – Dicotyledons
Order: Lamiales
Family: Lamiaceae ⁄ Labiatae
Genus: Pycnanthemum
Species: P. flexuosum
Binomial name
Pycnanthemum flexuosum
(Walter) Britton, Sterns & Poggenb.
PYCN FLEX dist.jpg
Natural range of Pycnanthemum flexuosum from USDA NRCS Plants Database.

Common names: Appalachian mountainmint, Savanna mountain-mint

Taxonomic notes

Synonyms: Pycnanthemum hyssopifolium Bentham; Koellia hyssopifolia (Bentham) Britton; Koellia hugeri Small


"Herbaceous perennials with elongate rhizomes and erect, quadrangular freely branched stems. Inflorescence compact cymules, often head-like, arranged in thryses or terminal at the ends of branches. Calyx 5-toothed, zygomorphic to actinomorphic; corolla zygomorphic, 2-lipped, upper entire or notched, lower 3-lobed. Stamens 4, usually exserted; stigmas 2-clet, exserted."[1]

"Plant canescent; stems 4-11 dm tall, the angles sharp to rounded. Leaves elliptic to elliptic-lanceolate, 1.5-5 cm long, 3-15 mm wide, acute to obtuse, crenate with 1-4 teeth on each margin, rarely entire, base cuneate to rounded; petioles 0.5-5 mm long. Inflorescence head-like, flat-topped to high-domed corymb, each cymules 2-4 cm broad, becoming somewhat open in fruit; bracts canescent, aristate, often whitened. Calyx slightly zygomorphic , tube 4-4/5 mm long, teeth usually white, acicular, erect to spreading, 2.3-3.3 mm long; corolla white to lavender, 4-6 mm long. Mericarps dark brown, 1-1.3 mm long, oblong-ovoid, long bearded at apex."[1]


It is found in moist to wet pinelands, pocosin margins, savannas, and bogs.[2]



In the Coastal Plain in Florida and Georgia, P. flexuosum can be found in low pinelands near pond edges, swales bordering cypress-gum swamps, open annually burned pine stands, well drained slopes, and in flats between the hills of longleaf pine forests.[3] It can also be found in drying loamy sand of grassy roadsides, floodplain clearings along rivers, open marshy areas, boggy areas, fields, and a swale in a burned and cutover upland longleaf pine savanna.[3] Associated species include pine, oak, cypress, sweetgum, and longleaf pine.[3]

Pycnanthemum flexuosum is an indicator species for the Upper Panhandle Savannas community type as described in Carr et al. (2010).[4]


This species has been observed to flower from June through September.[2][5]

Fire ecology

Populations have been known to persist through repeated annual burning.[6]

Conservation, cultivation, and restoration

Cultural use

Photo Gallery

References and notes

  1. 1.0 1.1 Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. Manual of the Vascular Flora of the Carolinas. 1964, 1968. The University of North Carolina Press. 918. Print.
  2. 2.0 2.1 Nelson, Gil. Atlantic Coastal Plain Wildflowers: A Field Guide to the Wildflowers of the Coastal Regions of Virginia, North Carolina, South Carolina, Georgia, and Northeastern Florida. Guilford, CT: FalconGuide, 2006. 62. Print.
  3. 3.0 3.1 3.2 Florida State University Robert K. Godfrey Herbarium database. URL: Last accessed: July 2015. Collectors: Loran C. Anderson, Ed Keppner, Lisa Keppner, R. A. Norris, Robert K. Godfrey, Steve L. Orzell, R. F. Doren. States and Counties: Florida: Bay, Jefferson, Leon, Wakulla, Washington. Georgia: Grady, Thomas. Compiled by Tall Timbers Research Station and Land Conservancy.
  4. Carr, S.C., K.M. Robertson, and R.K. Peet. 2010. A vegetation classification of fire-dependent pinelands of Florida. Castanea 75:153-189.
  5. Nelson, G. PanFlora: Plant data for the eastern United States with emphasis on the Southeastern Coastal Plains, Florida, and the Florida Panhandle. Accessed: 19 MAY 2021
  6. Platt, W.J., R. Carter, G. Nelson, W. Baker, S. Hermann, J. Kane, L. Anderson, M. Smith, K. Robertson. 2021. Unpublished species list of Wade Tract old-growth longleaf pine savanna, Thomasville, Georgia.