PRINCIPLES OF CLASSIFICATION. 33 



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

 former has declared that the number of the Coty- 

 ledons appeared to him to afford a sure basis, or 

 primary source of discrimination for a Natural Sy- 

 stem. He soon found what he thought an excep- 

 tion in Nymphcea, 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 eco- 

 nomy of Seeds have been more closely investigated. 



87. Gaertner and Jussieu have shown that the Albu- 

 men (62 : 3) advantageously serves in the natural 

 arrangement and discrimination of Plants. This 

 however is liable to as many exceptions, in the de- 

 tail, as almost any other source of characters. 



&8. Plants with a simple undivided Embryo (62 : 1) 

 are termed Monocotykdones, ormonocotyledonous; 

 the upper end of that organ being presumed to per- 

 form the necessary functions of a Cotyledon, with 

 respect to air, in the earliest stage of germination. 

 Hence the term in question may properly be re- 

 tained, though originally meant to apply to the se- 

 parate, 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 no particular 

 D 



