288 THE EMBRYO. 



no seed is perfect, or capable of vegetation, 

 however complete in external appearance. 

 Linnaeus, after Caesalpinus, names it the 

 Corculum, or Little Heart, and it is the 

 point whence the life and organization of 

 the future plant originate, as we have al- 

 ready explained, p. 96. In some seeds it 

 is much more conspicuous than in others. 

 The Walnut, the Bean, Pea, Lupine, <&c., 

 show the Embryo in perfection. Its inter- 

 nal structure, before it begins to vegetate, 

 is observed by Gaertner to be remarkably 

 simple, consisting of an uniform medullary 

 substance, enclosed in its appropriate bark 

 or skin. Vessels are formed as soon as the 

 vital principle is excited to action, and parts 

 are then developed which seemed not previ- 

 ously to exist, just as in the egg of a bird. 

 In position, the Embryo is, with respect 

 to the base of the whole flower or fruit, ei- 

 ther erect, as in the Dandelion and other 

 compound flowers, reversed as in the Um- 

 belliferous tribe, or horizontal as in the Date 

 Palm,/. 199 b, Gcertner, t. 9- In situation 

 it is most commonly within the substance 

 of the seed, and either central as in Um- 



