CHAP. II. 
CALYX. 
135 
the same time acquires the property of twining round any 
body within its reach, and so of supporting the stem, which 
is too feeble to support itself. Such rachises form what is 
called a spurious cirrhus, or a cirrhus peduncularis, and are a 
striking exception to the general law that the cirrhus takes its 
rise from the petiole or midrib. 
6. Of the Calyx. 
The cali/x is the most exterior integument of the Flower, 
consisting of several verticillate leaves, either united by their 
margins or distinct, usually of a green colour, and of a ruder 
and less delicate texture than the corolla. 
Authors have long disputed about the definition of a calyx, 
and the limits which really exist between it and the corolla : 
the above, which is copied from Link, seems to be the only 
one that can be considered accurate. The fact is, that in 
many cases they pass so insensibly into each other, as in Caly- 
canthus and Nymphaea, that no one can say where the calyx 
ends and the corolla begins, although it is evident that both 
are present. Linnaeus, indeed, thought that it was possible 
to distinguish them by their position with regard to the 
stamens, asserting that the divisions of the calyx are opposite 
those organs of the corolla alternate with them ; but, if this 
distinction were admitted, the corolla of the Primrose would 
be an inner calyx, which is manifestly an absurdity. Jussieu 
defines a calyx by its being continuous with the peduncle, 
which the corolla never is ; and this may seem in some cases 
a good distinction ; but there are plenty of true calyxes, of all 
Papaveraceous and Cruciferous plants, for instance, in which 
the calyx is deciduous, and not more continuous with the 
peduncle than the corolla itself. The only just mode of dis- 
tinguishing the calyx seems to me to be to consider it in all 
cases the most exterior verticillate series of the integuments 
of the flower within the bracts, whether it be half-coloured, 
deciduous, and of many pieces, as in Cruciferae ; membranous 
and wholly-coloured, as in Mirabilis ; green and campanulate, 
or tubular, as in Laurus and Lythrum. Upon this principle, 
whenever there is only one series of floral integuments, that 
K 4 
