LAMIACEAE 1177 
places and roadsides, various provinces, Ala. to La. and Mass. Nat. of Eu.— 
Sum.—fall. 
36. MENTHA [Tourn.] L. Perennial erect or diffuse herbs.  Leaf- 
blades toothed or incised. Flowers in dense axillary cymes, these sometimes 
dis Ed. in spike-like panicles. Calyx nearly regular, the lobes shorter than 
the tube. Corolla obscurely 2-lipped: upper lip mostly notched: lower lip of 3 
ids equal lobes. Stamens 4.—About 30 species, natives of the north temper- 
ate zone.—S MINT 
Flower-clusters all axillary, not in terminal spikes I. ARVENSES. 
Flower-clusters, at pee st most of them, peepee iad in terminal 
spike-like panicles II. SPICATAE. 
I. ARVENSES 
Stem and branches glabr ous or with short seattered hairs: 
calyx glabrous or nearly so, except for the eu lobes. 1. M. gentilis. 
Stem and branches n retrorse or spreading hairs: calyx 
pubescent all ov 
Stem and Branches. "with Short retrorse or retrorse-appressed 
hairs: larger calyx-lobes deltoid: calyx-tube closely pubes- 
Buc. with short hairs. 2. M. arvensis. 
Stem and branches with long lax or spreading hairs: larger 
calyx-lobes uA lanceolate : calyx-tube loosely pubes- 
cent with long hairs 3. M. canadensis. 
II. SPICATAE 
Flowers in short and stout raceme-like panicles, or clustered i 
Calyx, at least the 1 ; se ae 
em and leaves copiously pubescent : eee ovate 
or orbicular-ovate: calyx pubescent all ov 4. M. aquatica. 
Stem and leaves glabrous: leaf-blades elliptic, or lanceo- 
E te: ealyx with pubescent lobes. 5. M. piperita. 
labrous 6. M.citrata. 
Pio in Blandos or relatively slender, often elongate spike- 
i o longer calyx-lobes as long as the tube or 
leaf-blades sessile. 
Stem and ATOT not canescent : calyx-tube glabrous or 
nearly so: eorolla-tube not exceeding the calyx. T. M. spicata. 
Stem and inflorescence unes cant or villous- ore cones calyx- 
tube copiously pubescent: corolla-tube much exceeding the 
calyx 8. M. rotundifolia. 
1. M. gentilis L. Stem 2-7 dm. pens glabrous or nearly so: leaf-blades oval, 
ovate, praed or elliptie, 1.5-5 em. lon ne serrate, the foral ones not con- 
spicuously reduc ed, with petio see ofte 
lo d UM than the ond m iE 1 
long; tub E ous or nearly "go: 
corolla lavender or lilac; upper lip notched. 
—Stream-banks, waste- a nd roadsides, 
a provinces MS of Coastal inr. Ga. 
to Ia. and N.S. Nat. of Eu.—Sum.-fall. 
2. M. arvensis L. Stem 4 dm. tall or less, 
often diffuse, copiously, often closely. pale- 
pubescent: le af- bla ines = elliptic, or oval, 
ong, coarsely serrate above the 
the upper lip mostly notched —-Stream- banks, waste-places, and about ee 
