568 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



ular head. Epidermal cells of both surfaces more or less tabular, 

 the walls being but slightly undulate. 



Powder. Dark green; non-glandular hairs frequently consider- 

 ably twisted, 1- to 7-celled, thin-walled, smooth, frequently arranged 

 in stellate groups of 6 to 15, and spreading from the base; glandular 

 hairs with 1-celled stalk and 4- to 8-celled glandular head; pollen 

 grains spheroidal about 0.025 mm. in diameter, and with numerous 

 spinose projections; tracheae spiral, annular or reticulate, slightly 

 lignified ; sclerenchymatous fibers thin-walled, nonlignified and with 

 few simple pores. 



Constituents. A bitter, somewhat acrid principle, marrubiin 

 0.02 to 4 per cent, which forms prismatic crystals and is sparingly 

 soluble in water; several other bitter principles; a volatile oil; a 

 resin; and tannin. 



Allied Plants. Black horehound or Marrubium peregrinum, an 

 herb of the old world, possesses ovate or lanceolate, dentate-serrate, 

 grayish, hairy leaves and flowers having straight calyx-lobes. Ballota 

 nigra (Fam. Labiatse) has cordate, rough-hairy, dark green leaves, 

 pale purple flowers and a disagreeable odor. Water horehound or 

 Lycopus europseus possesses ovate-lanceolate, lobed or divided 

 leaves, the calyx lobes being triangular. 



Adulterant. The commercial drug consists at times of Ballota 

 hirsuta. (U. S. Dept. Agric.) 



MENTHA PIPERITA. Peppermint. The leaves and flowering 

 tops of Mentha piperita (Fam. Labiatse), a perennial herb (Fig. 240) 

 indigenous to Europe, naturalized in the eastern and central United 

 States and Canada, and cultivated in Michigan and New York. 

 Peppermint should be collected during dry weather, in August and 

 September, when the plant is in flower, and carefully dried and pre- 

 served. Peppermint is cultivated in Michigan chiefly for its volatile 

 oil. This State produces annually over 6800 K. of peppermint oil. 

 Wayne County, in New York State, produces 1480 K. ; Indiana State, 

 1280 K., and other localities about 40 K. annually. Japan pro- 

 duces about 70,000 K. annually; England, 9000 K.; France, 3000 

 K.; Russia, 1200 K.; Germany, 800 K., and Italy, 600 K. 



Description. Stem quadrangular, 1 to 3 mm. in diameter, pur- 

 plish-green, with scattered deflexed hairs, internodes 1.5 to 5 cm. in 

 length. Leaves ovate-lanceolate, opposite, 1.5 to 8 cm. in length, 

 0.5 to 2.5 cm. in breadth; summit acute; base acute or rounded; 

 margin sharply serrate; upper surface dark green, midrib and veins 

 rose-colored, the latter diverging at an angle of about 60, curving 

 upward and uniting near the margin; under surface light green, 



