124 ORGANOGRAPHY. BOOK I- 



Under particular circumstances bracts have received the 

 following ])eculiar names : — 



When they are empty, and terminate the inflorescence, they 

 form a coma^ as in Salvia Horminum. In this case they are 

 generally enlarged and coloured. 



If they are verticillate, and surround several flowers, they 

 constitute an involucre. In Umbelliferous plants, tlie bracts 

 which surround the general umbel are called an universal 

 involucre ; and those which suri'ound the umbellules a partial 

 involucre, or involucellum. In Compositae, the involucre 

 often consists of several rows of imbricated bracts, and has 

 received a variety of names, for none of which does there 

 appear to be the least occasion. Linnaeus called it calyx 

 communis, Necker ■perigynandra communis, Richard jjeriplior- 

 anthium, Cassini periclinium. There is often found at the 

 base of the involucre of Compositae an exterior rank of 

 bracts, which Linneeus called calyculus ; and such involucres 

 as were so circumstanced calyx calyculatus. Cassini restricts 

 the term involucre to this ; but it seems most convenient to 

 call these exterior bracts hractlets, and to say that an involu- 

 cre in which they are present is hasi bractcolatus, bracteolate 

 at the base. 



Another and very remarkable form of the involucre is the 

 cupula {Ji(j. 67.). It consists of bracts not 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 indurated bracts : in the Beech it forms a sort of 

 coriaceous valvular spurious pericarp : in the Hazel Nut 

 ijlg. G5.) it is foliaceous and lacerated: in the Yew it is fleshy 

 and entire, with no appearance of bract. 



The name squama or scale is usually applied to the bracts 

 of the catkin ; it is also occasionally used to indicate any 

 kind of bract which has a scaly appearance. 



The bracts which are stationed upon the receptacle of 

 Compositae, between the florets, have generally a membranous 

 texture and no colour, and are called palea, Englished by 

 some botanists chaff of the receptacle. The French call this 

 sort of bract paillette, Cassini squamelles {Jiy. G4.). 



In Palms and Aroidea? there are seated, at the base of the 



