THE FLOWER 235 



5. If a breeder wished to produce a sweet-scented daisy or pansy, how 

 would he make his selections? (260.) 



6. Which would he the more useful for his purpose, a plant that showed 

 a general tendency to variability, or one that remained steadily fixed to 

 its type? (260.) 



7. What could he do to break the type ? (263.) 



8. Would an intelligent breeder set out to produce edible roots and 

 tubers from wheat or barley? (263.) 



9. Would he think it worth while to try to develop a fleshy fruit from 

 a filbert or a walnut tree ? From a haw ? From sheepberry and black 

 haw? From tupelo (ogeechee lime) ? (263.) 



10. Suppose a florist should wish to change the color of a rose from pink 

 to deep red ; how could he hasten the process ? (257, 263.) 



11. Explain why it is so much easier to produce new varieties of plants 

 when there are already many kinds in existence, as, for example, the rose, 

 peach, and chrysanthemum. (255, 256; Exps. 78, 79.) 



VIII. ECOLOGY OF THE FLOWER 



A. The Prevention of Self-pollination 



Material. — Any kind of unisexual flowers obtainable. Some good 

 examples for illustrating points mentioned in the text are : for spring and 

 early summer, catkins of almost any of our common forest trees, — oak, 

 hickory, willow, poplar, etc.; tassels and young ears of early corn; for 

 summer and early fall, flowers of late corn, and of melon, squash, pump- 

 kin, or others of the gourd family. Examples of dichogamy are : evening 

 primrose, showy primrose {Oenothera speciosa), willow herb (Epilobium), 

 dandelion, artichoke, sunflower, or any of the composite family; of dimor- 

 phism: English primrose (Primula), loosestrife (Pulmonaria), bluets 

 (Houstonia), partridge berry; cleistogamic: fringed polygala, violets. 

 Peanuts, while not technically classed as cleistogamic, are strictly close- 

 fertilized, and approach the type so nearly that they may be used as an 

 illustration. 



266. Ecology is the study of plants and animals in relation 

 to their surroundings. The principal modifications that 

 flowers undergo in this respect are in adapting themselves 

 for (1) pollination, and (2) protection. 



267. Unisexual flowers. — The advantages of cross fer- 

 tilization were shown in the last two sections. It was also 



