NATURAL METHOD. 105 



which are not multiplied in this way, and unprovided with flowers. 

 This is, in fact, the course followed ; we ordinarily designate the 

 first of these divisions under the name of cot.yle donous or pha- 

 nerogamous plants, and the second under the name of acotyle'- 

 donous or crypto' gamous plants. 



21. The phanerogamous (from the Greek, phaneros, evident, 

 and gamos, marriage) or cotyle' donous plants all resemble each 

 other in the most important particulars of their organization, but 

 nevertheless very greatly differ from each other ; in some, the 

 seed contains but a single coty'ledon, and the stem is en'dogen- 

 ous ; the others have seeds provided with two or more cotyledons, 

 and an ex'ogenous stem ; consequently we divide them into two 

 groups, which are called monocoty 'ledons and dicotyledons. 



22. Among the crypto' gamous plants, there are some which 

 are composed exclusively of cellular tissue, and do not possess 

 any distinct organs that are analogous either to roots, stems, or 

 leaves; there are others which, although composed chiefly of cellu- 

 lar tissue like the first, often acquire vessels at a certain period of 

 their development, and are provided with parts analogous to tho 

 roots and leaves of ordinary plants. In order that the classifies* 

 tion of these plants be natural, that is, the expression of the more 

 or less important resemblances or differences they present, we 

 must, therefore, form them into two divisions ; that of cellular 

 plants properly so called, and that of semi-vascular plants. 



23. We subdivide the monocotyle'donous and dicotyle'donous 

 plants into classes according to the structure of their flowers, and, 

 to characterize the groups thus formed, we ordinarily take into 

 consideration, first, the absence or existence of a corolla, &c., 

 then we make a distinction between the monopetalous and 

 polypetalous corolla ; then we consider the manner of insertion 

 of the stamens or petals when they possess stamens. Finally, 

 the classes thus formed are subdivided into natural families ac- 

 cording as nature has variously modified the general mode of 

 organization of the seed, of the fruit, of the flower, &c. 



The following table, in which we have placed the most import- 

 ant natural families, shows at a glance the successive degrees 

 through which we arrive at the division of the vegetable king- 

 dom, according to the natural method or classification of Jus- 

 sieu : 



21. In what respects do phanerogamous plants differ from each other? 

 How are phanero'gamous plants divided ? 



22. How do crypto'gamous plants differ from each other? How are 

 they divided ? 



23. On what principle are these divisions subdivided ? 



