\ 



34 THE LABIATE FAMILY. [Mentha. 



heads or spikes, or axillary and distant. Calyx of 5 teeth, regular 

 or slightly 2-lipped. Corolla with a short tube and a campanulate 

 4-lobed limb, the upper lobe rather broader and sometimes slightly 

 notched. Stamens 4, equal and erect, the anthers 2-celled. Nuts 

 smooth, not bordered. 



A natural genus, not numerous in species, but widely diffused over 

 the greater part of the globe without the tropics, and most of the 

 species, from the variety of situations to which they will adapt them- 

 selves, vary so much as to render their exact definition almost hopeless. 

 Many of them also propagate so readily from suckers, that individual 

 varieties are perpetuated so as to assume the appearance of species. 

 Almost all the species vary in the stamens, in some individuals 

 much longer than the corolla, in. others included within the tube, 

 and often barren; and in several species individuals occur with all 

 the leaves crisped and cut, and have been published as distinct, under 

 the names of M. crispa or crispata. Hybrids also probably occur, and 

 may have been the origin of some supposed species, such as M. gentilis, 

 Sole., which are not now to be found wild. [No fewer than fourteen 

 species, with twenty- one varieties, are admitted into the London Cata- 

 logue of British Plants (1886.)] 



Whorls of flowers in terminal spikes or heads. 

 Leaves mostly sessile. Flowers in spikes. 

 Leaves and stem downy or hairy. 



Leaves narrow-ovate or lanceolate I. M. silvestris. 



Leaves broadly ovate or orbicular . . 2. M. rotundifolia. 



Leaves and stem glabrous 8. M . viridis. 



Leaves all shortly stalked. 



Flowers in cylindrical or elongated spikes . . . . 4. M. piperita. 

 Flowers in terminal, globular or ovoid heads (rarely with 



a few dense' clusters below the terminal one) . . 6. M . aquatica. 

 Whorls of flowers all axillary, the last (terminal) pair of leaves 



having no flowers or only a very small whorl. 

 Flowering stems ascending or erect. Leaves coarsely cre- 



nate. 



Throat of the calyx not closed with hairs. 

 Calyx tubular, with narrow teeth . . . . 6. M. sativa. 



Calyx campanulate, with short teeth . . . . 7. M. arvensit 

 Flowering stems prostrate. Leaves small. Throat of the 



calyx closed with hairs 8. M. Pulegium. 



1. M. silvestris, Linn. (fig. 780). Horse M. Rootstock, as in most 

 Mints, more or less creeping, the stems 1 to' 2 feet high, erect, slightly 

 branched, and, as well as the whole plant, more or less hoary with a 

 short close down. Leaves closely sessile, broadly lanceolate or narrow- 

 ovate. Flowers small and numerous, in dense cylindrical spikes, 1 to 

 2 inches long, usually several together, forming an oblong terminal 

 panicle. 



In wet pastures, and waste places, along ditches, &c., in temperate 

 and southern Europe and Russian and* central Asia, but does not 

 extend far north. In Britain, it is a doubtful native, and rare in the 

 northern counties. Fl. summer, rather late. 



2. M. rotundifolia, Linn. (fig. 781). Round-leaved M.Au erect 

 perennial, like M. silvestris, but coarser, greener, and more hairy. 

 Leaves broadly ovate or orbicular, much wrinkled, green above and 

 whitish underneath. Spikes of flowers terminal and cylindrical, more 

 slender than in the last, 1 to 2 inches or rather more in length, forming 



