390 COMPOSITE. [part ii. 



which is so called from the root looking as though 

 a part had been bitten off, has the same kind 

 of flower-head as the Dipsacus, but the recep- 

 tacle is flat, and the involucre much smaller. 

 In some of the species of Scabious, the florets 

 of the outer ring resemble those of the ray in 

 flowers of the Compositse. The leaves of the 

 genus Scabious are as variable as those of the 

 genus Valeriana, scarcely two species being 

 alike. 



ORDER CYII.— CALYCERE^. 



Obscure American plants, nearly allied to 

 Compositse. 



ORDER CVIIL— COMPOSIT.'E. (See Chap. VI. P. 98.) 



Plants with heads of florets on a common 

 receptacle, surrounded by an involucre. The 

 florets are of three kinds, viz., ligulate, tubular, 

 and bilabiate ; the heads consisting sometimes 

 entirely of florets of one kind, and sometimes 

 with ligulate florets forming the outer ring, 

 called the ray, and tubular flowers forming the 

 centre, called the disk. The calyx continues on 

 the ripe fruit, and its limb is frequently cut into 

 a kind of fringe called the pappus. The fruit 

 is of the kind called an achenium, that is, dry 

 and bony, and continuing enveloped in the per- 

 sistent calyx, but without adhering to it. 



