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Subfamily

VI. Subfam. Lamioideae Harley (2003)

Subfam. Stachyoideae (Dumort.) Luerss. (1882); Briq. in Engl. & Prantl (1895) et auct. mult., p.p., typ. incl.

Subfam. Prasioideae (Benth.) Thomé (1889)

Subfam. Pogostemonoideae P.D. Cantino, Harley & Wagstaff in Harley & Reynolds (1992).

Description

Rhizomatous perennial herbs, glabrous or subglabrous below inflorescence, hairs simple; leaves mostly sessile, often amplexicaul, the lowest sometimes petiolate; inflorescence racemoid, flowers subsessile; bracteoles absent; calyx actinomorphic, somewhat inflated in fruit, 5-lobed, lobes equal; corolla strongly 2-lipped, 4-lobed (1/3), white to reddish violet, posterior lip flat to slightly hooded, usually entire or emarginate, tube exannulate; stamens equal or anterior pair longer, filaments villous, thecae parallel, not confluent, suture bordered with 1-6 (-10) small teeth; disc with abaxial lobe equal to twice as long as ovary; stigma-lobes equal to subequal; nutlets trigonous, glabrous, smooth or rarely verrucate.  2n = 38, 76.  Twelve species, northern Canada to northern Mexico. Physostegia virginiana (L.) Benth. is widely grown as an ornamental and sometimes naturalized elsewhere. 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 (Cantino 1982).  The other parent is presumably extinct.

Distribution

Native to:

70 Subarctic America
71 Western Canada
72 Eastern Canada
73 Northwestern U.S.A.
74 North-Central U.S.A.
75 Northeastern U.S.A.
76 Southwestern U.S.A.
77 South-Central U.S.A.
78 Southeastern U.S.A.
79 Mexico

Publication

Physostegia Benth., Edward's Bot. Reg. 15: sub t. 1289 (1829); Cantino, Contr. Gray Herb. 211: 1-105 (1982).

Species found in RBG Kew living collections

2004-2817 Physostegia virginiana 'Summer Spire'  PERH   133 04 
1994-2775 Physostegia virginiana Benth.     111 10   :  111 21 
1969-33862 Physostegia virginiana Benth.    F 751 HPG-E 

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© Royal Botanic Gardens, Kew