129 



ated in order that it may set seed. The following experi- 

 ment made by F. A. Sirrine on the college grounds, indicates 

 clearly that self-fertilizatiotn does not occur in red clover. 

 Two plants were covered with cheese cloth to prevent insects 

 from getting in. In one plant nothing was done to see if 

 self-pollination could take place. In the second case, which 

 was a white spur of red clover, artificial pollination was 

 effect with its own pollen. In neither case was seed obtained. 

 Whenever pollen from another variety was used seed set. 

 Many grasses are eross-fertilized. Hackel'^ says: "In 

 some hermaphrodite flowers, cross-fertilization is so much 

 the rule that they have lost the power of effectual selt-fertili- 

 zation, as in rye." 



Cucurbits. . Some years ago the writer made some ex- 

 periments in crossing cucurbits. It was difficult to get 

 seed when pollen from the same vine was used. Prof. 

 Bailey had previously shown this to be true He says: 

 "The species are so exceedingly variable that all the hybrid 

 individuals may be unlike, so that there can be no crossing 

 between identical stock; and, if in-breeding is attempted, it 

 may be found that the fiowers will not in-breed. And the 

 refusal to in-breed is all the more strange because the sexes 

 are separated in different flowers upon the same plant. In 

 other words, in my own experience, it is very diflicult to get 

 good seeds from squashes which are fertilized by a flower 

 upon the same vine. Th« squashes may grow normally to 

 full maturity, but be entirely hollow, or contain only empty 

 seeds. In some instances the seeds may appear to be good, 

 but may refuse to grow under the best conditions. Finally, 

 a small number of flowers may give good seeds. I have 



13 The true grasses. English translation, Scribner and Southworth. p. 18. 



