PRINCIPLES OF CLASSIFICATION. 33 



bryo (62: 1), and the Cotyledons (62:2); and 

 the former has declared that the number of the 

 Cotyledons appeared to him to afford a sure basis, 

 or primary source of discrimination, for a Natural 

 System. He soon found what he thought an 

 exception in Nymp/uea, but was deceived in that 

 instance. The above principle, doubtless, is good, 

 but some correction of the commonly received 

 ideas and terms is become necessary, since the 

 structure and economy of Seeds have been more 

 closely investigated. 



87. Gaertner and Jussieu have shown that the Al- 

 bumen (62 : 3) advantageously serves in the na- 

 tural arrangement and discrimination of Plants. 

 This, however, is liable to as many exceptions, in 

 the detail, as almost any other source of characters. 



88. Plants with a simple undivided Embryo (62: 1) 

 are termed Monocotyledones, or monocotyledonous; 

 the upper end of that organ being presumed to 

 perform the necessary functions of a Cotyledon, 

 with respect to air, in the earliest stage of germi- 

 nation. Hence the term in question may properly 

 be retained, though originally meant to apply to 

 the separate, and usually copious, Albumen, of such 

 plants, visible in Corn, Palms, &c. 



89. Plants whose Embryo divides at the top into two 

 parts or lobes, which are the Cotyledons (62 : 2), 

 are named Dicotyledones, or dicotyledonous. In 

 some few instances, as the Fir tribe, there are 

 numerous Cotyledons; but such plants differ in 



D 



