INFLORESCENCE. 



37 



depressed axis is called the common receptacle (clinanthium) . As in the mnbel, the 

 head is usually bracteate, each flower springing from the axil of a bract. There 



150. Scabious. (Japitulum. 



151. Trefoil. Capital uin. 



152. Marigold. Capitulnm with involucre. 



should hence be as many bracts as flowers, but, owing to the crowding of the flowers, 

 some of the bracts are usually suppressed. The outer bracts, or those below the 

 outer flower, form the involucre (w-- 

 volucrum, periclinium, Marigold, fig. 

 152). The bracts of the centre flowers 

 are usually reduced to scales, bristles, 



153. Camomile. 



Paleate receptacle, cut 



vertically. 



154. Cornflower. 



Bristly receptacle, cut 



vertically. 



155. Onopordon. Alveolate receptacle, cut Vertically. 



or hairs. The receptacle is paleate (r.paleatum), when covered with scale-like bracts 

 separating the flowers (Camomile, fig. 153) ; setose (r.setosum), when these are bristly ; 

 such are often cut into fine hairs (Cornflower, fig. 154) ; pitted (r. alveolatum}, when 

 the flowers are seated in depressions, separated by variously shaped membranes, which 

 represent the bracts (Onopordon, fig. 155). When these inner bracts are absent 

 the receptacle is described as naked (r.nudum, Dandelion, fig. 156). Sometimes the 

 base of the head is naked, or only protected by some normal leaves (Trefoil, fig. 151), 

 but each flower may still be accompanied by a bract. 



The inflorescences of Dorstenia Contrayerva, and of the Fig (hypanthodium), 

 are also heads. In Dorstenia (fig. 157) the receptacle is much depressed or slightly 



