79 
natural Family of Plants called Composite. 
existence, in several genera of Composite, of five vessels alter¬ 
nating with those, and which I considered secondary in this order, 
though they occupy the place of the primary vessels in other fa¬ 
milies: and it is this inverted disposition, indicated in the greater 
part of the class by the primary being the only vessels existing, 
which I have considered as of material importance in determin¬ 
ing the limits of Composite, though by no means as affording an 
essential practical character for the whole class. 
In the passage quoted from M. Cassini (the only one I can find 
relative to the subject in the memoir in which it occurs), the 
existence of five nerves or vessels in the tube of the corolla, 
alternating with its laciniae, is stated, but their division and dis¬ 
position in the lacinise are not noticed; it is at the same time to be 
inferred from the terms of the passage, that no other vessels exist 
in the tube of the corolla: and it is equally evident that, so far from 
announcing this disposition of vessels as a discovery, or peculiar 
to the order, the author rather considers it either as a fact already 
known, or as the usual structure. That M. Cassini was not then 
aware of the importance of the fact which he had imperfectly 
stated, appears likewise from his having, many months after his 
memoir was read, and at a time when he says he had finished his 
analysis of the corolla, proposed a name for the class, taken from 
a supposed peculiarity in the structure of the filament, a name 
which he is now inclined to abandon for one derived from the dis¬ 
position of vessels in the corolla. 
Since my attention has been again turned to the subject, I have 
endeavoured to collect all that has been observed on the nerves 
or 
