ON THE ASCLEPIADEJE. 



*3 



natural series ; but it is, I apprehend, no longer 

 so, to distinguish the two orders by definitions 

 derived from the usual source. Such at least is 

 the opinion I have been led to form from all that 

 I have seen published respecting them, as well as 

 from that I have lately had an opportunity of ob- 

 serving in New Holland. 



As, however, both these families are already 

 too extensive, it becomes expedient rather to at- 

 tempt their subdivision into smaller groups, which 

 may possibly admit of more accurate limitation, 

 than to unite them into one vast order, the 

 distinguishing characters of which, could they be 

 obtained, must probably be extremely vague, and 

 clogged with numerous exceptions. Such a sub- 

 division, it seems to me, may be easily made of 

 the Apocineae, by employing a character at once 

 obvious and important, and which while it pre- 

 serves the natural series unbroken, has the addi- 

 tional advantage of dividing the order into two 

 nearly equal parts. To one of these which in- 

 cludes the genus Apocynum, the name of Apo- 

 cineae will of course remain. 



The consideration of the other, which from 

 one of its most remarkable genera, I propose 

 naming as clepi ade^e forms the chief subject of 

 the following essay ; but the more completely to 

 illustrate it, I have subjoined new, and I trust 

 amended characters of the genera of the most 

 nearly related section of the Apocineae strictly so 

 called. The sipgular structure of the stamina 



