124 



TAXONOMY. 



ceed in their growth without passing into each other. Thus 

 we see leaves grow together, which, in the Lonicerae, constitute 

 tinder the flow er an entire leaf, so that we say they have com 

 pletely united. Thus we every day see in the Umbellatae, two 

 fruits united, which only separate when they are fully ripe. In 

 the same manner, we find the parts of the involucra of many 

 Umbellatae growing together, especially in the species Bupleu^ 

 rum and Seseli, so as to lead us to the conclusion, that the ca- 

 lyces of compound flowers are nothing else but united involu- 

 cra, — as is proved by their transition into leaves in the calyx 

 of Bwphthalmum, in the Acmella of Richard^ in the Georgia^ 

 Wild, and in the Sigesheckia. The distinction between Trcb- 

 gopogon and Urospermum, Scop, also leads us to the same 

 conclusion, because in the latter the parts of the calyx are 

 united into one body, whilst in Trogopogon they are disjoined. 

 In these examples, therefore, it is evident that a union of the 

 leaflets of involucrum takes place, rather than that the calyx 

 deserves to be considered as a single and independent body. 



186. 



What has now been said of the calyx is applicable also to 

 the corolla. There is a regular vmion of the usually-sepa- 

 rated parts of the corolla, of which we have obvious examples 

 in some papilionaceous flowers, particularly in Trifolium^ 

 and even in the vexillum of the Lotus. In like manner, 

 many monopetalous flowers may be regarded as made up 

 of parts that originally stood free ; and it is evident in what 

 manner the forms of Cyphia and Phyteuma pass into imi- 

 tations of the corolla in the other Campanuleae. 



187. 



A similar disposition to united growth belongs to filaments, 

 whose analogy to petals strikes every person upon an atten- 

 tive consideration. When we consider, that among papiliona- 

 ceous flowers and leguminous plants, the numerous tribe of So- 

 phoreae have free standing filaments, whilst the tribe of Spar- 

 tese have them united into one bundle, both tribes will ap- 

 pear to be related to the Diadelphous plants, because we ob- 

 serve frequent transitions from the one tribe to the other. 



