LAMIACEAE. 



329 



Plants glabrous, or nearly so. 



Spikes narrow, mostly interrupted ; leaves nearly or quite sessile. 1. M. spicata. 

 Spilies tiiick. mostly dense ; leaves petioled. 



Leaves lanceolate to oblong, acute. 2. M. piperita. 



Leaves ovate, obtuse or the upper acute. 3. M. citrata. 



Plant tomentose-puberulent ; leaves rugose-reticulated. 4. M.rotundifolia. 



1. Mentha spicata L. Spearmint. 

 (Fig. 354.) Perennial hj leafy sto- 

 lons; stem erect, l°-2° high. Leaves 

 lanceolate, sessile or short-petioled, 

 sharply serrate, acute or acuminate, the 

 largest about 3' long; whorls of flow- 

 ers in spikes which become 2'-4' long 

 in fruit, the one terminating the stem 

 surpassing the lateral ones; bracts 

 subulate-lanceolate, ciliate; calyx cam- 

 panulate, its teeth subulate, nearly as 

 long as the tube; corolla glabrous. [M. 

 viridis L.] 



Common in wet or moist grounds. 

 Naturalized. Native of Europe. Widely 

 naturalized in North America. Flowers 

 in summer and autumn. 



naturalized 



2. Mentha piperita L. Pepper- 

 mint. (Fig. 355.) Perennial by 

 subterranean suckers; stem l°-3° 

 high. Leaves lanceolate, petioled, 

 dark green, acute, sharply serrate, 

 glabrous on both sides, or pubescent 

 on the veins beneath, the larger IV- 

 3V long; whorls of flowers in spikes, 

 which are obtuse, and become l'-3i' 

 long in fruit, the middle one at length 

 overtopped by the lateral ones ; bracts 

 lanceolate, acuminate; calyx tubular- 

 campanulate, glabrous below, its teeth 

 subulate, usually ciliate, one-half as 

 long as the tube or more ; corolla 

 glabrous. 



Frequent in marshes and ditches. 

 Naturalized. Native of Europe. Widely 

 in summer and autumn. 



