THE ECONOMIC BIOLOGY OF PLANTS 



453 



It is the seed of a small tropical tree growing in South and Central 

 America, Africa, and Ceylon. From the " cocoa bean," as it is 

 called, are made cocoa, chocolate, and cocoa butter. It must be 



a 



FIG. 141. Coconut. 



A , fruit, showing husk cut vertically through the center, revealing the hard 

 shell of the nut. 



B, nut viewed from below, showing the lines (a, a, a) along which the three 

 pistils are united; and between them the three germ pores, from the lower one 

 of which, ordinarily, the single germ emerges in sprouting. 



C, lengthwise section through the fruit sprouting; notice the thick husk, 

 into and through which the young roots grow, the hard shell of the nut (black) 

 within which is the layer of solid seed food (coarsely dotted), and the liquid 

 food or "milk" (white) into which the enlarging cotyledon or seed leaf (finely 

 dotted) pushes its way and acts as an organ of absorption. (Warming.) The 

 husk is smooth and grayish brown, and is largely composed of coarse, tough 

 fibers. From Sargent. 



observed that cocoa has nothing whatever to do with the coco- 

 nut which is a palm fruit while still another plant (coca) furnishes 

 from its leaves the dangerous drug cocaine. 



