vatiiral Famih/ of Plants called Composita, Q5 



reconciles the opposite statements of Koenig and Roxburgh; for 

 I find that at the time of flowering the envelope of each floret is, 

 as Roxburgh has figured it, distinct from the ovarium, with which, 

 however, in a more advanced stage its tube becomes firmly united ; 

 a fact that sufficiently accounts for Kcenig's description. 



'J'here is here, therefore, a nearer approach to a true perian- 

 thium than in the involucrura of Lagasca ; but the expansion of 

 the flowers being, as in that genus, from centre to circumference 

 of the capitulum, I consider the envelope of CasuUa as unques- 

 tionably an involucrum,and the genus consequently belonging to 

 I'olyganiia segregata. 



1 may here remark, that the name Polygamia segregata, invented 

 by Linneus for those genera of Compositae with densely aggre- 

 gate capitula, is calculated to give an erroneous idea of the nature 

 of the structure ; the opposite term Polygamia congregata being, 

 according to the view now taken, obviously more proper for those 

 genera, at least, whose involucra contain several flowers. It is 

 not unlikely, indeed, that Linneus himself was aware of the true 

 nature of the inflorescence of these genera; but the term Polyga- 

 mia congregata would not have suited the artificial arrangement 

 which lie adopted in his subdivisions of the class, nor his includ- 

 ing in it the order Moiiogainia ; for with this order the single 

 flowered genera of Polygamia segregata must then have been 

 confounded. 



It is a curious circumstance, that the order of expansion in 

 Compositae does not depend on the number of flowers actually 

 existing, but on the eff'ort, if 1 may so term it, made to produce 

 them, manifested by the presence of an involucrum or common 

 calyx, which is in some cases reduced to a single flower. The 

 fact at the same time contributes to prove, that the whole na- 

 tural class is formed on that plan of dense aggregation of flowers, 



lor 



