?48 or THB INVQLUCRUM. 



the genera of umbelliferous plants, for 

 which purpose the latter deemed the part 

 in question very important. But accord- 

 ing to the laws which Linnaeus had laid 

 down, the parts of the flo-v^'er and fruit 

 alone were to afford generic .characters, 

 and the most sound botanists have ever 

 since kept to this rule, with infinite advan- 

 tage over less correct ones, however ready 

 to derive ideas respecting the natural habit, 

 and seconclary characters, of a genus, not 

 only from the inflorescence and bracteas, 

 but even from the leaves, stipulas, or other 

 parts. Linnseus and Artedi, therefore, were 

 obliged to consider the invohtcra and invo- 

 htcella, the former accompanying the ge- 

 neral and the latter the partial umbels, as 

 a sort of calyx, and the umbel altogether as 

 one aggregate flower, composed of florets 

 united by a common radiated receptacle. 

 Consequently a cyme must be considered 

 in the same light ; nor are reasons wanting 

 in support of this hypothesis, which we 

 shall consider after having first explained 

 all the carts of fructification. 



In Euphorbia, however, the term hractea 



