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MANUAL OF BOTANY 



basal region becomes converted into a flattened or even cup- 

 sbaped receptacle. The bracts of the lovper portion of the axis 

 Fig. 221. Fig. 222. 



Fig. 221. Compound umbel of Fennel. 

 a. General umbel. 6, 6, h. Partial umbels 



or umbellnles. Fig. 222. Simple umbel 



of a species of Allium. 



maybe aggregated together at the base of the receptacle and form 

 an involucre. In many cases, however, they are suppressed en- 

 FiG 223 tirely. Of this form of 



inflorescence we have 

 three varieties, the capitw- 

 lum, the ccenanthiwm, and 

 the hypanthodmim. 



o. The Oapitulum, 

 Anthodmim, or Head. — 

 This inflorescence is 

 usually formed by a num- 

 ber of sessile flowers or 

 florets crowded together 

 on a receptacle, and the 

 whole surrounded by an 

 involucre {fig. 223) ; but in 

 some cases the florets are 

 but few in number, and 

 from other capitula the 

 involucre is absent. The 

 receptacle, as we have 

 seen, may be either flat- 

 tened, as in the Cotton 

 Thistle (fig. 224); or 

 slightly convex, as in the Dandelion; or conical, as in the 



Fig, 223. Capituhim of Scabious (ScaMosa). 

 The outermost florets may be observeil 

 to be more expanded than the inner. 



