~The External Form of Plants.’ 127 
| the fruit. Sometimes it even takes part in the formation of 
the fruit, as in Zvapa, the four horns of the fruit being here 
formed by the lignification of the calyx-teeth.! Particularly 
noteworthy is the production of the appus from the limb of 
the calyx. This peculiar form is especially characteristic of 
Composite ; the calyx continues to grow after the withering 
of the corolla, and either a crown of simple hairs or pz/ose pap- 
pus (Figs. 235, 236), or a p/wmose pappus of branched hairs 
Fic. 235.—Pilose sessile pappus of Fic. 236.—Pilose stipitate pappus of 
Senecio. dandelion. . 
(Figs. 237, 238),is formed from its teeth, and subse- \ 
quently crowns the fruit. The pappus may either be 
sessile as in the groundsel (Fig. 235), or s¢zpzfate as in the dan- 
delion (Fig. 236), from the development of the upper part 
of the calyx-tube, in the form of a stalk which bears the 
_ feathery crown. The pappus, again, may be dentate, or 
coronate (Fig. 239), the calyx-teeth remaining in the latter 
case undeveloped, and being transformed into small broad 
hairs which form, as it were, a crown to the fruit. In addi- ~ 
tion to the Composite, instances of a pappus occur in 
-Valerianaceze and Dipsacaceze. The chicory, Cichorium 
1 [The fleshy calyx-tube of the rose, apple, pear, &c., unites with 
the pistil to form a pseudocarp (see p. 146).—ED.] . | 
