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the pistil is fertilized by insects carrying sticky pollen; the other 

 by movement of the wind carrying the pollen. If I should believe 

 my records, in attempts to cross trees. I might have a cross between a 

 birch and an alder, in Avhich the pollen is carried by the wind. I tried 

 once to hybridize pines. I put some pitch pine pollen on the female 

 flower of another species and seed resulted. I did this the second year 

 and again I got seed. The third year I put bags on the female flowers 

 before I could see them developing. Then I got no seeds. I believe 

 that the pollen which had caused the seed to set in the preceding 

 instances had come from the south for pe'rhaps hundreds of miles. 



There are times when the pollen of the staminate plant is all shed 

 before the pistillate gets ready. Sometimes we have a plant that is 

 self sterile. I have experimented with pollen from several different 

 nut trees and also with the Norway spruce. Then again, there are 

 abnormal cases; sometimes there is parthenogenesis. The jimson weed 

 is the first plant which has ever been reproduced by parthenogenesis. 

 Since that was discovered, an investigator in California has found 

 a similar case in fruit developed without pollination. 



One of the most important conceptions in heredity is its effect upon 

 characters and factors. Take the Japanese bean here shown for 

 example, one dark bean and one mottled. In the next hybrid genera- 

 tion we find three mottled and one dark. That is the familiar "three 

 to one" ratio of ^Nlendels law. We believe now, that all. or at least 

 a very large proportion of the heredity characters in plants of all 

 kinds may be due to a series of factors; but the habit of growth of the 

 plant is due to a single factor. We have the case here of a second 

 generation of the weeping mulberry that I crossed with the white mul- 

 berry. As a result there was an average of three erects to one weeping 

 one. Certain characteristics may be made up of the inter-action of a 

 large number of factors. This will give a little idea as to the com- 

 plexity of Mendel's law. 



How do we get new characters in nature? New types are due to 

 the rearrangement of previously existing characters, just as with the 

 old-fashioned kaleidoscope, where you turn the crank and get new 

 pictures. Another way is by the sudden appearance of new factors. 



I wish to speak about one effect of hybridization, which is really 

 connected with heredity factors, the vigor which occurs when we cross 

 different varieties, species, or even races. In my experience certain 

 types that have been naturally contrasted finally lose vigor, and after 



