te 
50 THE FERTILISATION OF FLOWERS. [CHAP. 
pollen and shrivelled up, the stigmas mature. Self- 
fertilisation cannot take place. The more conspicuous 
these flowers are rendered by association, the larger 
the number of insects by which they are visited. 
In Viburnum (Guelder Rose) the flowers are 
arranged on a similar principle to the Umbellifers, 
but the outer circle of flowers produce neither stamens 
nor pistil, the corolla being developed to a very large 
size instead. This has the effect of rendering the 
flower-head very conspicuous, and, together with the 
powerful perfume exhaled, is an attraction to the 
insects, who ramble over the flowers collecting and 
depositing pollen as they go. For this they are re- 
warded with a plentiful supply of honey. 
Fic. 58. FIG. 59. Fic. 60. 
In the Composite order of plants we have a similar 
arrangement, of which the Common Daisy may be 
taken as.a type. The “flower” of this plant is in 
reality a cluster of flowers or “florets.” The advan- 
tages of this arrangement are—(1) the flowers are 
rendered more conspicuous; (2) the honey is more 
easily accessible from the close proximity of the 
flowers, consequently more insects visit it; and (3) 
