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III. On the Asclepiadece, a Natural Order 

 of Plants separated from the Apocinece of 

 Jussieu. 



By Robert Brown, Lib. Lin. Soc. 



{Read Mh November 1809. J 



The vast additions to the number of species which 

 botany is constantly receiving, while they make 

 a natural arrangement absolutely necessary to the 

 general botanist, render it at the same time pro- 

 portionally difficult. For though there are still 

 many tribes of plants easily distinguishable even 

 by a superficial observer, yet there are others, that 

 hitherto have been thought abundantly distinct, 

 which can no longer be circumscribed by means 

 of characters taken from their organs of reproduc- 

 tion. This is perhaps now the case with the 

 rubiaceje and apocineje of Jussieu. It is true, 

 that to an experienced observer, it may still be 

 practicable to refer the greater part, perhaps the 

 whole, of these plants to their proper places in a 



