6o2 



BOTANY AND PHARMACOGNOSY. 



Europe. The two latter plants are naturalized in New Jersey, the 

 New England States and Eastern Canada. A number of species 

 of Rhododendron contain, in addition to andromedotoxin (see 

 page 357), the same principles found in Uva Ursi. Marsh tea 

 or narrow-leaved Labrador tea (Ledum palustre), growing in 

 the Northeastern United States and Canada, as well as North- 

 ern Europe and Asia, contains ericolin, arbutin, an ethereal oil 

 (the principal component of which is Ledum camphor), valer- 

 ianic, acetic and butyric acids. (Compare also Chimaphila.) 



Fig. 259. Buchu leaves showing oil glands which give the leaves the glandular- 

 punctate appearance: i, Barosma crenata oralis; 2, B. crennlaia latifolia; 3, B. betuUna; 

 4, B. serratifolia; s, Empleurum ensatum; 6, dehiscent fruit of B. crenulata; 7, flower 

 of the same. After Tschirch. 



BUCHU. The leaves of several species of Barosma (Earn. 

 Rutacese), a shrub indigenous to Cape Colony. There are two 

 chief commercial varieties : ( i ) Short Buchu obtained from B. 

 hctulina and (2) Long Buchu. obtained from B. serratifolia, the 

 short buchu being official (p. 306; Fig. 259). 



Short Buchu. Obovate. rhomboid-obovate, ovate or ellip- 

 tical or somewhat cuneate ; 9 to 18 mm. long, 6 to 12 mm. broad; 

 apex obtuse, somewhat recurved ; base acute or cuneate ; margin 

 sharply dentate or denticulate and with an oil-secretion reservoir 

 at the base of each tooth ; upper surface yellowish-green, glab- 



