204 PLANT ORGANS OR PARTS OF PLANTS. 



oboval, sometimes elongated, obtused at the apex, from 

 I to 2 cm. long and 7 to lo mm. broad, smooth, with 

 crenulate or serrate margins. At the base of each tooth 

 is situated a large oil-gland. Other smaller glands are 

 distributed throughout the leaf. 



These two official varieties yield the short buchu of 

 commerce. Long buchu is obtained from Barosma 

 serratifolia, whose leaves are thin, linear, lanceolate, 

 about 3 cm. long, 5 mm. broad, tapering at both ends, 

 margins obtusely serrate, with a gland at each point, apex 

 truncate. All varieties are smooth, dark green in color, 

 paler on the under surface. The odor is strong, pepper- 

 mint-like. Taste, warm, aromatic, somewhat acrid. 



Long buchu is sometimes adulterated with the leaves of 

 Empleurum serrulatum. These are longer and narrower 

 than the genuine leaf, apex sharply pointed, margins 

 coarsely serrate. Their odor is distinct, taste acrid. 



Histology. — The upper epidermis, destitute of stomata, 

 is formed of a layer of tabular cells with cutinized, 

 thickened outer walls. On the surface, these cells appear 

 polygonal in outline, with straight sides. They are 

 filled with hesperidin. This occurs in irregular yellow 

 masses, amorphous, or in spherocrystals. Beneath the 

 epidermis is a layer of flat cells, rich in mucilage, which 

 swell up on contact with water and elongate in a direction 

 perpendicular to the surface of the leaf. Next within is a 

 layer of typical palisade cells covering the loose, irregular 

 leaf parenchyma. The lower epidermis bears numerous 

 stomata. Hesperidin crystals are also present here. 

 The fibro- vascular bundles are small, but slightly ligni- 

 fied, separated from each epidermis by a number of 

 colorless, thick-walled cells. The oil-glands are large at 

 the borders, occupying the entire space between the 

 upper and lower epidermis. They are enclosed in two 

 layers of tabular, thin- walled parenchyma. 



Powder — When fresh the powder is a light green, with 



