CHAPTER EIGHT 



THE RED SUNFLOWER 



I. THE red sunflower may be studied in illustration Mendeiian 

 of the principles of heredity and of plant breeding. Its { 



advantages for this purpose arise from the fact that its b y *&* red 



- i 111- 11 sunflower 



origin is known, and its whole history belongs to recent 

 times, since the rediscovery of Mendel's law. It is also 

 very easily grown, and the various crosses may be made 

 with little difficulty. It is only necessary to cover the 

 heads with paper bags before they come into flower, 

 and at intervals dust the stigmas with pollen from 

 another plant. The great amount of pollen produced 

 by the flower head, although reaching its own stigmas, 

 has no effect. The plants are always, with possible 

 rare exceptions, sterile with their own pollen. When 

 the summer is over and the seed is ripe, the heads 

 may be cut off, bags and all, and the seed garnered at 

 leisure. 



2. The sunflowers (Helianthus, which in Greek means Characters 

 sunflower) are peculiar to the Western Hemisphere. 

 They are most numerous in the United States east of 

 the Rocky Mountains, but extend south to the Andean 

 region of South America. The common garden sun- 

 flower (Helianthus annuus) is an annual, coming from 

 seed every year. Others are perennial, growing year 

 after year from the same clump ; while still others send 

 out underground branches, from which new plants arise, 

 the original roots and stems perishing at the end of the 

 season. All these plants are herbaceous ; that is, the 

 stems die at the end of summer or fall. 



Sunflowers belong to the great group of plants 

 called Composite. The so-called flower is really a flower 

 head, consisting of a disklike or more or less elevated 



51 



