162 
ORGANOGRAPHY. 
BOOK I. 
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, and 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 pe- 
duncle, 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 
distinguishing 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 Brassicaceae ; membran- 
ous and wholly-coloured, as in Mirabilis ; green and cam- 
panulate, or tubular, as in Laurus and Lythrum. Upon this 
principle, whenever there is only one series of floral integu- 
ments, that series is the calyx. A calyx, therefore, can exist 
without a corolla ; but a corolla cannot exist without a calyx, 
either perfect or rudimentary. 
The term Perianth is sometimes given as synonymous with 
calyx ; but this is an error. 
The word Perianth signifies the calyx and corolla com- 
bined, and is therefore strictly a collective term. It should 
only be employed to designate a calyx and corolla, the limits 
of which are undefined, so that they cannot be satisfactorily 
distinguished from each other, as in most Monocotyledonous 
plants, the Tulip and the Orchis for example. But since, 
even in such plants as these, there can be no reasonable doubt 
that the three outer floral leaves are the calyx, and the three 
inner the corolla (as is shown both by Tradescantia and its 
allies, in which the usual limits between calyx and corolla 
exist, and also by the usual origin of those parts in two distinct 
