V. SUMMARY OF DISTPJBUTIOX. 233 



III the list or summary here under explanation, the plants are 

 arranged after the usual manner, that is, in accordance with structural 

 classification, as understood by botanical systematists. But such an 

 arrangement has only faint relations with geography. Under no aspect 

 can it be said to bring plants together in accordance with their geo- 

 graphical connexions or similarities. The advantage of such a sum- 

 mary, so arranged, is that it places the leading geographical peculiarities 

 of each several species under the eye in a single line ; that line being 

 readily found by any botanist moderately conversant with systematic 

 classification. And the lines for differeut species can be compared with 

 each other at a glance. 



In the other lists which are to succeed the one under notice, on the 

 contrary, the names of plants are brought near together, or placed in 

 series, in accordance with their geographical relations; namely, ac- 

 cording to their frequency or infrequency, the area over which they are 

 diffused, the altitude to which they ascend, &c., &c. lu short, the 

 various similarities which will bring the plants near together in other 

 lists, and so constitute their arrangement, are those of distribution, not 

 those of structure. 



VOL. IV. a H 



