264 OBSERVATIONS ON THE NATURAL FAMILY 



where, though only five vessels are visible, they are erro- 

 neously made to pass through the axes of the laciniae. 



The only remaining author that notices these vessels is 

 M. Mirbel, who in the second part of his valuable Elemens 

 de Physiologie Vegetale et de Botanique, published in 

 1S15, introduces into his character of Compositae the fact 

 of the laciniae of the corolla being furnished with marginal 

 nerves. This observation, if not original, the author may 

 have adopted either from my essay already quoted, of 

 which he was in possession soon after its publication, or 

 from M. Cassini's third memoir, which was read to the 

 Institute of France six months after that essay appeared : 

 but he could not have derived it from the passage in that 

 author's second memoir, on which he rests his claim ; no 

 notice being there taken of the disposition of vessels in the 

 laciniae. 



In M. Cassini's memoir expressly on the Corolla of 

 Compositae, which was read to the Institute of France in 

 December 1814, and of which an abstract, by the author 

 82] himself, is given in a late number of the Nouveau Bul- 

 letin des Sciences, the disposition of vessels in the corolla 

 is expressed in the following terms : 



" Chacun des cinq petales dont se compose la corolle est 

 muni de deux nervures tres simples qui le bordent d'un 

 bout a l'autre des deux cotes, et confluent par consequent 

 au sommet." 



On this statement I have several remarks to offer. And 

 first, I object to its hypothetical language. Whatever 

 opinion may be formed of the theory here adopted by the 

 author, namely, that every monopetalous corolla is in 

 reality composed of several confluent petals ; a theory first 

 proposed by Linnaeus himself in his Prolepsis Plantarum, 

 and ably supported on different grounds by Mons. Decan- 

 dolle in his excellent Theorie Elementaire de la Botanique ; 

 I can see no advantage in adopting its language in stating 

 a fact of this kind, especially if proposed as a practical 

 character. 



For my own part, I consider this opinion as correct in 

 the sense in which it was held by Linnaeus, without, how- 



