33a. Leaves linear-oblong, acute at both ends (3 8 dm. high; sum- 

 mer) Hyssop, Hyssopus officinalis. 



33b. Leaves oblong to ovate, rounded at the ends (2 4 dm. high; 

 late spring) Bugle, Ajuga reptans. 



34a. Leaves ovate to oblong, acute; flowers pink, white, or pale 

 purple (6 15 dm. high; summer) Catnip, Nepeta cataria. 



34b. Leaves nearly circular or kidney-shape; flowers blue 

 (creeping; flowers in spring and summer) 



Ground Ivy, Nepeta hederacea. 



35a. Flowers in terminal spikes, or the lower axillary (3 8 dm. 



high; flowers pink-purple or white, summer) (Mint) 36. 

 35b. Flowers all in axillary whorls (flowers pink-purple or white, 



summer) (Mint) 38. 

 35c. Flowers in terminal capitate corymbed clusters (4 8 dm. high; 



flowers white or dotted with purple, summer) (Mountain Mint) 



36a. Leaves sessile or with very short petiole 



Spearmint, Mentha spicata. 

 36b. Leaves with manifest petioles 37. 



37a. Principal leaves less than half as broad as long 



Peppermint, Mentha piperita. 

 37b. Principal leaves more than half as broad as long 



Bergamot Mint, Mentha citrata. 



38a. Stem glabrous; leaves ovate to obovate (4 8 dm. high) 



Downy Mint, Mentha gentilis. 

 38b. Stem pubescent, at least on the angles (1 6 dm. high) 39. 



39a. Principal leaves distinctly petioled and somewhat rounded at 

 base Wild Mint, Mentha arvensis. 



39b. Leaves tapering to the base 40. 



40a. Leaves and stem pubescent 



Wild Mint, Mentha arvensis var. canadensis. 

 40b. Leaves glabrous; stem pubescent on the angles only 



Wild Mint, Mentha arvensis var. glabrata. 



4 la. Leaves linear; calyx-teeth awl-shape 



Mountain Mint, Pycnanthemum flexuosum. 

 41b. Leaves narrowly lanceolate; calyx-teeth triangular-ovate 



Mountain Mint, Pycnanthemum virginianum. 



42a. Stems decumbent to diffuse; leaves cordate to nearly cir- 

 cular (stems 2 5 dm. long or high; flowers in spring and 

 summer) (Dead Nettle) 43. 



42b. Stem erect; leaves palmately cleft; calyx-teeth spiny (6 15 

 dm. tall; flowers pink, in summer) 



Motherwort, Leonurus cardiaca. 



42c. Stems erect or ascending; leaves ovate-lanceolate to linear 

 (summer) 45. 



