natural Family of Plants called Compositec. 
77 
“ The whole of Compositac agree in two remarkable points of 
structure of their corolla; which, taken together at least, materi¬ 
ally 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 disposi¬ 
tion of its fasciculi of vessels or nerves; these, which at their 
origin are generally equal in number to the divisions of the co¬ 
rolla, 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 corre¬ 
sponding laciniae, within whose apices they unite. These, as they 
exist in the whole class and are in great part of it the only ves¬ 
sels observable, may be called primary. In several genera, how¬ 
ever, other vessels occur, alternating with the primary, and occu¬ 
pying the axes of the laciniae: in some cases these secondary ves¬ 
sels being most distinctly visible in the laciniae, and becoming 
gradually fainter as they descend the tube, might be regarded as 
recurrent; originating from the united apices of the primary 
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 base, is necessarily con¬ 
nected with this structure, which seems also peculiarly well 
adapted to the dense inflorescence of Compositae; the vessels of 
the corolla and stamina being united and so disposed as to be 
least liable to suffer by pressure.” 
At the date of this publication I certainly had no knowledge of 
any similar observations having been previously made: but I now 
see 
