370 BOTANY AND PHARMACOGNOSY. 



Mentha species. — The plants are nearly glabrous, diffusely 

 branching herbs, which form leafy stolons that are perennial 

 (Figs. 67, 175). The leaves and flowering tops of both Mentha 

 piperita (p. 631) and Mentha spicata (p. 632) are official. 



2. Volatile oils of the following plants are official: 

 Rosmarinus officinalis is a shrub growing in the Mediterranean 



countries. The plant has linear, coriaceous leaves, and bluish, bila- 

 biate flowers, the middle lobe of the lower lip of the corolla being 

 large, concave, and toothed on the margin. The flowering tops 

 yield from i to 1.5 per cent, of oil which is CQmf)osed of 15 to 18 

 per cent, of borneol; about 5 per cent, of bornyl acetate; and 

 pinene, camphene, camphor and cinneol. There are two commer- 

 cial varieties of the oil, the Italian and French, the latter having 

 the finer odor. 



Lavandula officinalis (garden lavender) is a shrub growing in 

 the Northern Mediterranean countries, as well as in England. The 

 leaves are linear, coriaceous ; the flowers are small, light blue, 

 bilabiate, with a tubular calyx, and occur in opposite cymes 

 (verticillasters). 



The oil is derived from the fresh flowering tops, the flowers 

 yielding about 0.5 per cent. Two kinds of oil are on the market, 

 namely, French and English. The French oil contains 30 to 45 

 per cent, of 1-linalyl acetate ; linalool ; geraniol, both of which 

 latter constituents occur free and; as esters. The English oil con- 

 tains about 5 to 10 per cent, of linalyl acetate and a slight amount 

 of cineol. Spike lavender (Laz'endula Spica) is sometimes dis- 

 tilled with true lavender (p. 371). 



Thymus vulgaris (garden thyme) is a small shrub having 

 linear or linear-lanceolate leaves, and pale blue flowers with 

 strongly bilabiate, hairy calyx that occur in axillary cymes. The 

 plant grows in the mountains of Southern France. The herb 

 contains from 0.3 to 0.9 per cent, of volatile oil, which is of a 

 dark reddish-brown color, and contains from 20 to 25 per cent, of 

 thymol ; and cymene, 1-pinene, borneol and linalool. The Spanish 

 oil of thyme contains from 50 to 70 per cent, of carvacrol, but no 

 thymol. 



3. Of OTHER PLANTS OF THE LABiAT^E which are of interest, 

 the following may be mentioned : 



