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TEXTBOOK OF BOTANY 



petals ; and by the further fact that just below the head 

 are many bracts that look like sepals. Really, however, 

 a single head of a sunflower, a daisy, or a dandelion contains 

 many separate small flowers. 



276. Compound Flower Clusters. — The kinds of clusters 

 so far mentioned are simple; they have, in each case, a 

 peduncle whose branches are the pedicels. But the branches 

 of the peduncle may themselves branch, and so the pedicels 

 may be branches of the third or fourth order. Such repeated 

 branching gives rise to a compound flower cluster. A com- 

 mon form of compound cluster is the panicle, a compound 

 raceme. The tassel of the Indian corn is a panicle. The 

 flowers of the elder and of the mountain ash are borne in 

 compound cymes. Compound umbels are common ; they 



are borne by many mem- 

 bers of the parsley family, 

 including the parsley, the 

 carrot, and the parsnip. 



277. Pollination: How It 

 is Brought About. — By pol- 

 lination is meant the carry- 

 ing of the pollen grains 

 from the anther that pro- 

 duced them to a stigma of 

 the same or of another 

 flower. The pollen of the 

 great majority of angio- 

 sperms is carried to the 

 stigmas either by the wind, 

 as in the corn and other 

 grasses ; or by insects, as 

 in the bean. Some agents 

 other than the wind and 

 insects bring about pollina- 

 tion in certain cases. Thus, 



Fig. 155. — Tape-grass {Vallisncria 

 spiralis). The plant on the left bears 

 staminate flowers which, still unopened, 

 are breaking away and rising to the 

 surface of the water. The plant on 

 the right bears a pistillate flower on a 

 long stalk which reaches to the surface. 

 After Kerner. 



