natural Family of Plants called Composite. 85 
to Composite. It exists also in Ernodea, in which the lateral nerves, 
though they give out externally a few branches, observe the same 
course, and terminate in the same manner in the laciniæ as those 
of Composite. A similar disposition is observable in certain 
genera of Solanacez, as Datura and Cestrum, though in these the 
lateral nerves are more ramified; and their trunks generally less 
distinct in the laciniæ. It appears therefore that, in adopting 
M. Cassini's theoretical expression for the vascular structure of 
point of adhesion, and iu such a degree that the corresponding branches of the neighbour- 
ing segments unite with each other considerably above the middle of the tube, forming a 
common trunk, which is continued to the base of the ovarium; the five trunks thus formed 
uniting internally with those from which the filaments originate, and externally with the 
axes of the opposite segments of the calyx. The middle nerves of the segments of the 
corolla are in like manner continued below the point of cohesion to the real base of th 
tube. ; 
. The analogy of this disposition of vessels in the corolla of Goodenovie to that of Com- 
posite is obvious. To assimilate entirely the two structures, it is only necessary to suppose 
a deeper division of the five primary vessels of Composite, and a continuation of the tube 
of the corolla below its apparent base to that of the ovarium. That this is its real origin, is 
rendered not improbable both from the analogous structure now described in the family of 
Goodenoviæ, and from the manifestly hypogynous corolla of Brunonia; a genus in many 
respects still more nearly related to Composite, though differing in the disposition of the 
vessels of its corolla, | 
The more direct proof of this origin, derived from an examination of the surface itself, 
can hardly, perhaps, be expected where the parts are generally so small, and where, as I 
conceive, the surface of the pericarpium in many cases depends less on. that of the cohering 
envelopes, than on the proper figure of the ovarium itself, as seems to be likewise the case 
in Umbellate, — - an + s | 
There are however a few cases in which this opinion respecting the origin of corolla in 
Composit may derive some additional-support from the appearance of the surface of the 
ovarium, as in Marshallia and Hymenopappus, in both: of which genera, but particularly in: 
the former, it is marked with ten longitudinal striæ, of which the five stronger are continued 
into the five nerves. of the corolla, the remaining five ending abruptly at the apex of the 
ovarium. 
the 
