Pycnanthemum

Mountain mints
	Short-toothed mountain mint (Pycnanthemum muticum)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Lamiales
Family:	Lamiaceae
Subfamily:	Nepetoideae
Tribe:	Mentheae
Genus:	Pycnanthemum; Michx.
Synonyms
	Furera Adans. ; Brachystemum Michx. ; Koellia Moench ; Tullia Leavenw. ; Pycnanthes Raf. ;

Pycnanthemum is a genus of herbaceous plants in the mint family (Lamiaceae). Species in this genus are often referred to as "mountain mints" and they often have a minty or thyme-like aroma when crushed. All species of Pycnanthemum are native to the United States and Canada.^[1]^[2]^[3] The center of diversity for the genus is North Carolina with 13 of the 20 species having been collected therein. Nineteen of the 20 species of Pycnanthemum occur in the Eastern US and Canada, and one disjunct species (P. californicum) occurs in California and Oregon.

Pycnanthemum is derived from Greek. The Greek word "pyknos" has the meaning of "dense", "tight", or "close-packed".^[4]^[5] It was combined with "anthos" meaning flower to give the genus name.^[6]

Pycnanthemum belongs to the true mint subtribe (Menthinae),^[7] and it has been shown to be closely related to the Monarda, Blephilia, and the scrub mints of the Southeastern United States.^[8] Relationships within the genus remain unresolved. A complicated history of polyploidization paired with cryptic morphologies makes this a challenging group for systematists.^[9]

Species

Pycnanthemum albescens Torr. & A.Gray – white-leaved mountainmint – south-central US
Pycnanthemum beadlei (Small) Fernald – North Carolina, South Carolina, Virginia, eastern Tennessee, northern Georgia
Pycnanthemum californicum Torr. ex Durand – Sierra mint – California
Pycnanthemum clinopodioides Torr. & A.Gray – mid-Atlantic States, Tennessee, Indiana
Pycnanthemum curvipes (Greene) E.Grant & Epling – southeastern US
Pycnanthemum flexuosum (Walter) Britton, Sterns & Poggenb. – southeastern US
Pycnanthemum floridanum E.Grant & Epling – Florida mountainmint – Florida, southern Georgia
Pycnanthemum incanum (L.) Michx. – hoary mountainmint, hoary basil, wild basil – Ontario, most of US east of the Mississippi River
Pycnanthemum loomisii Nutt. – Loomis' mountainmint – southeastern US, Ohio Valley
†Pycnanthemum monotrichum Fernald – Virginia but extinct
Pycnanthemum montanum Michx. – southern Appalachians
Pycnanthemum muticum (Michx.) Pers. – short-toothed mountainmint – much of eastern US from east Texas to southern Maine
Pycnanthemum nudum Nutt. – Coastal Plain mountainmint – southeastern US
Pycnanthemum pilosum Nutt. ( = P. verticillatum var. pilosum) – hairy mountainmint, whorled mountainmint
Pycnanthemum pycnanthemoides (Leavenw.) Fernald – southern mountainmint – southeastern US, Ohio Valley
Pycnanthemum setosum Nutt. – awned mountainmint – southeastern + mid-Atlantic US
Pycnanthemum tenuifolium Schrad. – little-leaved mountainmint, slender-leaved mountainmint (= P. flexuosum auct. non Walter) – Quebec, Ontario, eastern + central US
Pycnanthemum torreyi Benth. – Torrey's mountainmint – eastern + east-central US
Pycnanthemum verticillatum (Michx.) Pers. – whorled mountainmint – Quebec, Ontario, eastern + central US
Pycnanthemum virginianum (L.) T.Durand & B.D.Jacks. ex B.L.Rob. – Virginia mountainmint – Quebec, Ontario, eastern + central US