Physostegia Benth.

Harley, R.M. et al. (2004). Labiatae, in The Families and Genera of Vascular Plants (K. Kubitzki, ed. in chief) VI: 167-275. Springer-Verlag, Berlin, Heidelberg, New York.

Morphology General Habit

Rhizomatous perennial herbs, glabrous or subglabrous below inflorescence, hairs simple

Morphology Leaves

Leaves mostly sessile, often amplexicaul, the lowest sometimes petiolate

Morphology Reproductive morphology Inflorescences

Inflorescence racemoid, flowers subsessile

Morphology Reproductive morphology Inflorescences Bracteoles

Bracteoles absent

Morphology Reproductive morphology Flowers Calyx

Calyx actinomorphic, somewhat inflated in fruit, 5-lobed, lobes equal

Morphology Reproductive morphology Flowers Corolla

Corolla strongly 2-lipped, 4-lobed (1/3), white to reddish violet, posterior lip flat to slightly hooded, usually entire or emarginate, tube exannulate

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens equal or anterior pair longer, filaments villous, thecae parallel, not confluent, suture bordered with 1-6 (-10) small teeth

Morphology Reproductive morphology Flowers Disc

Disc with abaxial lobe equal to twice as long as ovary

Morphology Reproductive morphology Flowers Gynoecium Stigma

Stigma-lobes equal to subequal

Morphology Reproductive morphology Fruits

Nutlets trigonous, glabrous, smooth or rarely verrucate.

Note

2n = 38, 76.  Twelve species. With a base number of 19, Physostegia is probably of amphiploid origin from parents with n = 9 and 10 (Cantino 1985b).  One parent may be Warnockia (n = 10), the genus with the closest phenetic relationship to Physostegia (Ca

Distribution

Northern Canada to northern Mexico.