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.]
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