LABIATJa. 413 



■WTiorls of flowers in tecminal spikes or heads. 

 Jjeaves inostli/ aessile. Flowers in spikes. 

 Leaves and stem downy or liaiiy. 



Leaves narrow-ovate or lanceolate 1 . Sorse M. 



Leaves broadly ovate or orbicular 2. Sound-leaved il, 



leaves and stem glabrous 3. Spear M. 



Leaces ail shortly stalked. 



Flowers in cylindrical or elongated spikes 4. Pepper M. 



Plowers in terminal, globular or ovoid heads (rarely with a 



few dense clusters below the terminal one) 5. Water M. 



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 crenate. 

 Throat of the calyx not closed with hairs. 



Calyx tubular, with narrow teeth 6. Whorled M. 



Calyx campanulate, with short teeth 7. Corn M. 



Flowering stems prostrate. Leaves small. Throat of the calyx 



closed with hairs 8. Pennyroi/al It. 



1. Horse Mmt. Mentlia sylvestris, Liun. 

 (Eug. Bot. t. 686.) 



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 plaut, 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, usuaUy several together, forming an oblong terminal 

 panicle. 



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

 southern Europe and Eussian and central Asia, but does not extend far 

 north. In Britain, it appears to be confined to England and Ireland, and 

 rare in the northern counties, tlie few Scotch localities indicated belonging 

 more probably to the following. Fl. summer, rather late. 



2. Round-leaved Mint. Mentha rotundifolia, Linn. 

 (Eng. Bot. t. 446.) 



An erect perennial, like the horse M., but coarser, greener, and more 

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

 wliitish underneath. Spikes of flowers terminal and cylindrical, more slender 

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

 somewhat spreading panicle. Flowers small, pale pink or sometimes white. 



Nearly as widely diftused over Europe and temperate Asia as the last, but 

 rather more of a western plant. It spreads also more readily as an accom- 

 paniment of cultivation. In Britain, rather more common than the horse M., 

 extending into Scotland and Ireland, but probably m many cases iutrodueed. 

 yi. summer, rather late. Specimens occur occasionally so nearly interme- 

 diate between the two species that it is difficult to say to which they belong 

 tmless seen growing in masses. 



3. Spear Mint. Mentha viridis, Linn. 



(Eng. Bot. t. 2424.) 



An erect or ascending perennial, with tlie narrow leaves sessile or nearly 



so, and the cylindrical terminal spikes of the horse M., but the stem and 



leaves are green and glabrous, although there are often hairs on the calyx 



and bracts. 



Chiefly known in Europe, Asia, and North America, as the common 

 Mint of gardens, and only found apparently wild in countries wliere it has 



2n 2 



