140 



STRUCTURAL BOTANY. 



[119, 120. 



the pedicels of an umbel become themselves umbels, 

 as in Caraway and most of the Umbelliferae, a com- 

 pound umbel is produced. Such secondary umbels are 

 called umbelletSj and the primary pedicels, rays. 



360. The panicle is a compound inflorescence 

 formed by the irregular branching of the pedicels of 

 the raceme, as in Oats, Spear-grass, Catalpa. A thyrse 

 is a sort of compact, oblong, or pyramidal panicle, as 

 in Lilac, Grape. 



361. A head or capitulum is a sort of reduced 

 umbel, having the flowers 



all sessile upon the top of 

 the peduncle, as in the 

 Button-bush, Clover. But 

 the more common exam- 

 ples of the capitulum are 

 seen in the Composites, 

 where the summit of the 

 peduncle, that is, the recep- 

 tacle, is dilated, bearing the 

 sessile flowers above, and 

 scale-like bracts around, as 



-i 

 an inVOlUCre. 



o n n. mi --L 7 



362. The CapltUl 



~ . , P, 



the Compositse is often 

 called a compound flower from its resemblance, the in- 

 volucre answering to a calyx, the rays to the corolla. 

 The flowers are called florets those of the outer cir- 

 cle, florets of the ray, generally differing in form from 

 those of the central portions, the florets of the disk. 



363. Of terminal inflorescence the following varie- 

 ties are described : cyme, fascicle (verticillaster), and 

 glomerule. 



446 



446) Vernonia fasciculatar - fl ower 8 in a discoid 



head with an imbricated involucre. 447, A single 

 flower remaining on the receptacle. 448, A fruit 

 -C crowned with the pappus. 449, Mulgedium a head. 

 OI 460 , A single flower remaining on the receptacle. 

 > -A. fruit with pappus. 



