CHAP. II. 
LEAVES. 
141 
botanists). It is one of the contrivances employed by nature 
to support plants by aid of others stronger than themselves. 
It was included by Linnaeus among what he called fulcra ; 
and has generally, even by very recent writers, been spoken 
of as a peculiar organ. But, as it is manifestly in most cases 
a particular form of the petiole, I see no reason for regarding 
it in any other light. It may, indeed, be a modification of 
the inflorescence, as in the Vine; but this is an exception, 
showing, not that the cirrhus is not a modification of the 
petiole, but that any part may become cirrhose. 
In some cases the petiole of a compound leaf is lengthened, 
branched, and endowed with the power of twusting round any 
small body that is near it, as in the Pea : it then becomes what 
is called a cirrhus petiolaris. At other times, it branches off 
on each side at its base below the lamina into a twisting 
ramification, as in Smilax horrida ; when it is called a cirrhus 
peduncular is. Or it passes, in the form of midrib, beyond the 
apex of a single leaf, twisting and carrying with it a portion 
of the parenchyma, as in Gloriosa superba ; when it is said to 
be a cirrhus foliaris. De Candolle also refers to tendrils the 
acuminate, or rather caudate, divisions of the corolla of 
Strophanthus, under the name of cirrhus corollaris. 
As another modification of the petiole, I am disposed to 
consider with Link (Elem. 202.) the singular form of leaf in 
Sarracenia and Nepenthes {fig- 58.), which has been called 
a pitcher [Ascidium, Vasculum). This consists of a fistular 
58 
