ERYTHROXYLON. COCA. 199 



tain table-lands. It is there extensively cultivated, 

 and recently also in India, Ceylon, and Java. The leaves 

 are collected from plants over one year of age, and are 

 slowly dried in the sun. Two varieties are commonly 

 found in the market, the Huanuco and the Truxillo. 



Description. — The Huanuco leaves have a brownish- 

 green color, are oval in shape, and vary from 4 to 8 

 cm. in length and from 2.5 to 2 cm. in breadth. Both 

 surfaces are glabrous, and the lateral veins are prom- 

 inent. The margin is entire, and the lamina tapers to- 

 ward both base and apex; the latter is acute and the 

 midrib projects in the form of a minute homy point. 

 The odor is faint but characteristic, and the taste slightly 

 bitter. 



Truxillo leaves are smaller, pale green, and more 

 fragile, hence usually more or less broken,* 



Powder. — This is greenish-brown ; if too yellow, it signi- 

 fies age or imperfect' drying. The Huanuco powder is 

 usually darker than that derived from the Truxillo 

 variety. 



The main histological elements found in the powder 

 are crystals, parenchyma, epidermis, hairs, vessels, and 

 fibres. The crystals are not abundant; they are of the 

 cubical (monoclinic) variety, usually quite flattened and 

 angular. They are found usually in crystal sacs, one 

 crystal being in each sac, and are present also in the 

 palisade cells; and also clustered about the bast fibres. 

 The average size of the crystals is about 3 to 10 microns. 

 The parenchyma is typical leaf parenchyma. It varies 

 considerably in size, is usually thin-walled, and has on the 

 upper sides of the leaf a single row of palisade cells, rich 

 in chlorophyll. 



The structure of the epidermis of the upper and lower 

 surfaces of the leaf is dififerent. The upper surface is 

 macroscopically smooth, though microscopically minutely 



♦Consult H. H. Rusby, "Coca Leaves," Druggists' Circular, 1903. 



