148 
ORGANOGRAPHY. 
BOOK I. 
Another form of the involucre is the cupula [fig. 66.). It 
consists of bracts not much developed till after flowering, 
when they cohere by their bases, and form a kind of cup. 
In the Oak the cupula is woody, entire, and scaly, with indu- 
rated bracts : in the Beech it forms a sort of coriaceous, 
valvular, spurious pericarp: in the Hazel Nut [Jig, 65.) it is 
foliaceous and lacerated.* 
In Euphorbia the involucre is composed of two whorls of 
bracts, consolidated into a cup, and assumes altogether the 
appearance of a calyx, for which it was for a long time 
mistaken. 
The name squama or scale is usually applied to the bracts 
of the catkin ; it is also occasional!)" used to indicate any kind 
of bract which has a scaly appearance. 
The bracts wdiich are stationed upon the receptacle of 
Compositae, between the florets, have generally a membranous 
texture and no colour, and are called palecE, Englished by 
some botanists chaff of the receptacle. The French call this 
sort of bract paillette, Cassini squamelles. 
In Palms and Araceae there are seated, at the base of the 
spadix, large coloured bracts, in which the spadix, during 
aestivation, is wholly enwrapped, and which may perhaps per- 
form in those plants the office of corolla. This is called the 
spathe {Jig. 83.). Link considers it a modification of the 
petiole. {Elementa, p. 253.) 
67 
* What has been called the cupula of the Yew is said by Schleiden to 
be a late developement of the primine of the ovule. 
