296 



FLOWERS 



due to the massing of their small flowers into good-sized 

 inflorescences. 



A. Advantages. — In connection with pollination, in- 

 florescences are an advantage ; that is, it is of advantage to 

 have the flowers in clusters rather than widely separated. 

 Whether pollination be accomplished by wind or by in- 

 sects, the same 

 thing is true. 

 As for wind-pol- 

 linated flowers, 

 evidently they 

 need to be ex- 

 posed in such 

 manner that the 

 pollen is likely 

 to be blown 



Fig. 117^. — Inflorescence and leaf of the waterleaf ^^Om them and 

 (.Hydrophyllum canadense) ; one of the spring flowering upon them. Ev- 

 plants often very abundant in woods. idently, also, ij: 



is good economy for the plant to expose flowers in clusters 

 rather than singly. It requires more of stem growth to 

 expose flowers borne singly than to expose an equal number* 

 borne in clusters. A further advantage is evident when 

 the stigmas of a number of clustered flowers form a pollen- 

 catching arrangement which would not be possible if the 

 flowers were not close together. This is illustrated by corn. 

 (See Figure loj.) Evidently the many threads of the silk 

 catch pollen better when they are together than they pos- 

 sibly could if they were separate. 



As for insect-polHnated plants, the nearer the flowers are 

 together, the more visits can be made by an insect in the 



