260 OBSERVATIONS ON THE NATURAL FAMILY 



77] Holland, appended to Captain Minders's Voyage to Terra 

 Australis. 



'To these observations I shall add some remarks on 

 certain genera of Compositae, which occur repeatedly 

 under different names in late systematic works, and 

 whose structure and limits appear to be imperfectly un- 

 derstood. 



My first observation relates to the peculiar disposition 

 of the nerves or vessels of the corolla of this family of 

 plants. 



In the essay already mentioned, which appeared early in 

 the summer of 1814, I have noticed this peculiarity in the 

 following terms -} 



"The whole of Composite© agree in two remarkable 

 points of structure of their corolla ; which, taken together 

 at least, materially assist .in determining the limits of the 

 class. The first of these is its valvular aestivation ; this, 

 however, it has in common with several other families. 

 The second I believe to be peculiar to the class, and hitherto 

 unnoticed. It consists in the disposition of its fasciculi of 

 vessels or nerves ; these, which at their origin are generally 

 equal in number to the divisions of the corolla, instead of 

 being placed opposite to these divisions, and passing 

 through their axes, as in other plants, alternate with them ; 

 each of the vessels at the top of the tube dividing into two 

 equal branches, running parallel to and near the margins of 

 the corresponding laciniae, within whose apices they unite. 

 These, as they exist in the whole class and are in great part 

 of it the only vessels observable, may be called primary. 

 In several genera, however, other vessels occur, alternating 

 with the primary, and occupying the axes of the lacinise : 

 in some cases these secondary vessels being most distinctly 

 visible in the lacunae, and becoming gradually fainter as 

 they descend the tube, might be regarded as recurrent; 

 originating from the united apices of the primary 

 78j branches ; but in other cases, where they are equally 

 distinct at the base of the tube, this supposition can hardly 

 be admitted. A monopetalous corolla, not splitting at the 



[} Vol. i, p. 30.] 



