21 



SPECIES XIV.-M E N T H A ARVENSIS. Linn. 



Platks MXXXVlll. MXXXIX, MXL. 



n,ih;; Journ. not. 1865, p. 251. 



M. arvensis, var. e. Beiith. in D.G. Prod. Vol. XII. p. 172. 



M. arvensis, var. a and /3. Hook. & Am. Brit. Fl. ed. viii. p. 325. 



Leaves spreading', shortly stalked, oval or ovate or oval-rliomboidal 

 or oblong-ovate, rounded or wedge-shaped at the base, slightly tapering 

 towards the apex, acute or subacute or obtuse, bluntly serrate or 

 crenate-serrate, more or less hairy on both sides, rarely subglabrous 

 except on the veins beneath. Flowers in whorls, which arc all separate, 

 beginning below or about the middle of the stem. Bracts similar to 

 tlie leaves, and usually equalling them in size, or the upper ones smaller, 

 uppermost ones Avithout flowers ; bracteoles strapshaped, acute, ciliated, 

 shorter than the flowers. Pedicels hairy or glabrous. Calyx hairy, 

 campanulate, scarcely longer than broad; teeth deltoid, acuminate, 

 acute or obtuse, about one-third the length of the tube, haiiy. Corolla 

 about twice as long as the calyx, hairy without and within. Nucules 

 rough with small [joiiits. 



Var. a, genuina. 



Plate MXXXVIII. 



Sole, Brit. Mints, p. 29. Pl. XTI. Bal-or, 1. c. p. 251. 



Stem short, generally much branched, thickly clothed with reflexed 

 hairs. Leaves not rugose, bluntly and shallowly serrate, about 

 twice as long as broad, more or less hairy all over, especially above. 

 Upper bracts scarcely diminishing in size. Calyx thickly hairy. 



Var. ^, nummularia. 

 Plate JIXXXIX. 

 M. nummuhii-ia, " Schrch." Baler, 1. c. p. 252. 



Stem elongated, slightly branched, rather sparingly hairy. Leaves 

 scarcely twice as long as broad, bluntly serrate, not rugose, sparingly 

 hairy on both sides. Upper bracts scarcely diminishing in size. 

 Calyx haiiy. 



Var. 7, agi-estis. 



Plate ilXL. 



M. agrestis, Sole, 1. c. p. 33. PI. XTV. Sm. E. B. ed. i. No. 2120. Baker, 1. c. p. 252. 



Stem elongated, erect, much branched, hairy. Leaves nearly as 



