Aquatic and Wetland Vascular Plants of the Northern Great Plains

Lamiaceae - The Mint Family

Perennial herbs, some aromatic, with square stems and simple, opposite, serrate or incised-toothed leaves. Flowers axillary or in terminal heads or spikes, often appearing verticillate, perfect, nearly regular to irregular; calyx 5-toothed or sometimes bilabiate, the lobes equal to unequal; corolla white, pink, blue or purple, sometimes spotted, often bilabiate, 5-lobed or 4-lobed by fusion, the lobes very unequal to subequal; stamens 4 or 2, epipetalous; pistil 2-carpellary, style slender, gynobasic, 2-cleft at the tip, ovary superior, 4-celled and 4-lobed, splitting into 4, 1-seeded nutlets at maturity.

Lead	Characteristic	Go To
1	Corolla regular or nearly so, the lobes subequal.	Lead 2
1	Corolla distinctly irregular, the lobes unequal.	Lead 3
2	Stamens 2; plants not strongly aromatic.	Genus Lycopus
2	Stamens 4; plants strongly mint-scented.	Genus Mentha
3	Upper lip of the corolla lacking, the lower lip prominent, the other 4 corolla lobes positioned on its lateral margins.	Genus Teucrium
3	Both upper and lower lips of the corolla well-developed.	Lead 4
4	Calyx with a rounded protuberance on the upper side, 2-lipped, not toothed.	Genus Scutellaria
4	Calyx without a dorsal protuberance, toothed, 2-lipped or not.	Lead 5
5	Flowers short-pedicelled, borne singly in the axils of short bracts, the inflorescence comprised of 1-several, terminal and lateral racemes.	Genus Physostegia
5	Flowers sessile and whorled, in a continuous or interrupted terminal spike.	Lead 6
6	Calyx strongly 2-lipped, unequally 5-toothed; spike dense, continous.	Genus Prunella
6	Calyx not strongly 2-lipped, with 5 equal or subequal teeth; spike interrupted.	Genus Stachys