X20 



LABIATAE. 



[Vol. Ill- 



4. Mentha longifolia (L.) Huds. 

 Horse Mint. (Fig. 2>^TJ.) 



Mentha spicala var. longifolia L. Sp. PI. 576. 1753. 

 Mentha longifolia Huds. Fl. .\ngl. 221. 1762. 

 Mentha sylvestris L. Sp. PI. Ed. 2, .S04. 1763. 



Perennial by suckers, canesccnt or puberulent 

 nearly all over; stems mostly erect, branched, or 

 simple, i°-2j-^° high. Leaves lanceolate, ovate- 

 lanceolate, or oblong-lanceolate, sessile, or very 

 short-petioled, acute at the apex, usually 

 rounded at the base, sharply serrate, i'-3' long, 

 yz'-Y)^' wide, sometimes glabrous above; whorls 

 of flowers in terminal narrow dense or inter- 

 rupted acute spikes, which become 2'-5' long in 

 fruit; bracts lanceolate-subulate, the lower equal- 

 ling or longer than the flowers; calyx tomentose 

 or canesccnt, its teeth subulate, one-half as long 

 as the campanulate tube; corolla puberulent. 



In waste places, Pennsylvania and New Jersey. 

 Naturalized from Europe. Called also Brook- or 

 Eish-Mint, and formerly Water-Mint. July-Oct. 



5. Mentha rotundifolia (L.) Huds. Round-leaved Mint. (Fig. 3178.) 



Mentha spicala var. rotundifolia L. Sp. PI. 



576. 1753. 

 Mentha rotundifolia Huds. Fl. Angl. 221. 1762. 



Perennial by leafy stolons, canesccnt or 

 tomentose-puberulent, somewhat viscid; 

 stems ascending or erect, simple or branch- 

 ed, usually slender, i)^°-2;^° high. Leaves 

 elliptic, or ovate-oblong, short-petioled, or 

 sessile and somewhat clasping by the sub- 

 cordate or rounded base, obtuse at the apex, 

 crenate-serrate with low teeth, i'-2' long, 

 9"-i5''' wide, more or less rugose-reticu- 

 lated beneath; whorls of flowers in terminal 

 dense or interrupted spikes which elongate 

 to 2'-^' in fruit; bracts lanceolate, acumin- 

 ate, commonly shorter than the flowers; 

 calyx-teeth setaceous, usually about one- 

 half as long as the tube; corolla puberulent. 



In waste places, Maine to North Carolina, 

 Texas and Mexico. Called also Apple Jlint, 

 Horse Mint, Wild Mint. July-Sept. 



6. Mentha alopecuroides Hull. Woolly 

 Mint. (Fig. 3179.) 



Mentha alopecuroides Hull. Brit. Fl. 221. 1799. 



Perennial by suckers, white-woolly; stem 

 stout, leafy, erect or ascending, simple or branch- 

 ed, i^'-^°-3° high. Leaves broadly oval, sessile, 

 or partly clasping by a subcordate or rarely 

 rounded base, obtuse at the apex, sharply and 

 rather coarsely serrate, pinnately-veiued, the 

 lower 2'-3' long, i>^'-2' wide ; spikes rather 

 thick, dense, stout, obtuse, 2^-3' long in fruit; 

 bracts lanceolate, shorter than the flowers; calyx- 

 teeth setaceous, one- half as long as the campan- 

 ulate tube, or more; corolla pubescent. 



Along roadsides, southern New York. New Jersey 

 and Pennsylvania to Missouri. Naturalized from. 

 Europe. July-Oct. 



