Genus 36. 



MINT FAMILY. 



149 



5-toothed. Corolla-tube shorter than the calyx, the limb 4-cleft, somewhat irregular, the 

 posterior lobe usually somewhat broader than the others, entire or emarginate. Stamens 4, 

 equal, erect, included or exserted, sometimes imperfect; filaments glabrous; anthers 2-celled, 

 the sacs parallel. Ovary 4-parted ; style 2-cleft at the summit. Nutlets ovoid, smooth. 

 [Name used by Theophrastus ; from the nymph Minthe.] 



About 30 species, natives of the north temperate zone. The more or less characteristic odors 

 of the species change during the progress of the life of the plant. Type species : Mentha spicata L. 

 * Whorls of flowers in terminal spikes, or some in the upper axils. 



Plants glabrous or very nearly so. 



Spikes slim, narrow, mostly interrupted ; leaves sessile, or nearly so. 

 Spikes thick, mostly dense, at first short ; leaves petioled. 

 Leaves lanceolate or oblong, acute. 

 Leaves ovate, obtuse, or the upper acute, subcordate. 

 Plants villous, hirsute or canescent, at least at the nodes. 

 Spikes slim or narrow, often interrupted. 



Leaves lanceolate or ovate-lanceolate, acute. 

 Leaves elliptic or ovate-oblong, obtuse, reticulated beneath. 

 Spikes thick (6"), dense, elongated or short. 



Leaves sessile ; spikes 1' 3' long ; plant canescent. 

 Leaves distinctly petioled, or the uppermost sessile ; spikes short. 

 Leaves simply serrate. 

 Leaves mostly incised, the margins crisped and wavy. 



** Whorls of flowers all axillary. 

 LTpper leaves much smaller than the lower. 

 Upper leaves not conspicuously reduced. 

 Stem pubescent. 



Leaves rounded or obtuse at the base. 

 Leaves narrowed, mostly cuneate at the base. 

 Stem glabrous or nearly so. 



i. Mentha spicata L. Spearmint. Lamb or 

 Common Mint. Our Lady's Mint. Fig. 3680. 



Mentha spicata L. Sp. PI. 576. 1753. 

 Mentha spicata var. viridis L. loc. cit. 1753. 

 Mentha viridis L. Sp. PI. Ed. 2, 804. 1763. 



Glabrous, perennial by leafy stolons ; stem erect, 

 branched, i-ij high. Leaves lanceolate, sessile or 

 short-petioled, sharply serrate, acute or acuminate 

 at the apex, narrowed at the base, the largest about 

 2'' long; whorls of flowers in terminal narrow acute 

 usually interrupted spikes, which become 2-4' long 

 in fruit, the one terminating the stem surpassing the 

 lateral ones; bracts subulate-lanceolate, ciliate, some 

 of them usually longer than the flowers ; calyx cam- 

 panulate, its teeth hirsute or glabrate, subulate, nearly 

 as long as the tube ; corolla glabrous. 



In moist fields or waste places, Nova Scotia to On- 

 tario, Minnesota, Washington, Florida, Texas and Cali- 

 fornia. Naturalized from Europe. Also in Bermuda. 

 Native also of Asia. Garden-, brown- or mackerel-mint. 

 Sage-of-bethlehem. July-Sept. 



1. M. spicata. 



2. M. piperita. 



3. M. citrata. 



M. longifolia. 

 M. rotundifolia: 



4. 



5. 



6. M. alopecuroides. 



7. M. aquatica. 



8. M. cripsa. 



9. M. Cardiaca,. 



M. arvensisr. 

 M. canadensis. 

 M. gentilis. 



2. Mentha piperita L 



Mentha piperita L. Sp. PI. 



Peppermint. 

 576- 1753- 



Perennial by subterranean suckers ; stems glabrous, 

 mostly erect, branched, i-3 high. Leaves lanceo- 

 late, petioled, dark green, acute at the apex, rounded 

 or narrowed at the base, rather firm, sharply serrate, 

 glabrous on both sides, or pubescent on the veins 

 beneath, the larger li'-3' long, i'-li' wide; whorls 

 of flowers in terminal dense or interrupted spikes, 

 which are thick and obtuse, and become i' 3' long 

 in fruit, the middle one at length overtopped by the 

 lateral ones ; bracts lanceolate, acuminate, not longer 

 than the flowers, or the lower occasionally folia- 

 ceous ; calyx tubular-campanulate. glabrous below, 

 its teeth subulate, ciliate, one-half as long as the 

 tube or more ; corolla glabrous ; style occasionally 

 3-cleft. 



In wet soil. Nova Scotia to Ontario and Minnesota, 

 south to Florida, Tennessee and Arkansas. Also in 

 California, Bermuda and Jamaica. Naturalized from 

 Europe. Lamb- or brandy-mint. July-Sept. 



