936 CALIFORNIA ACADEMY OF SCIENCES. 



Finally, fig forms appeared with a flask-like receptacle, 

 only open at the top or eye, and in order to exclude the 

 majority of depredating insects, this opening became 

 covered over with scales, as in our present figs, wild or 

 cultivated. 



If we again consider the flowers alone, we find that in 

 the lowest forms of figs, which must also have most re- 

 sembled the oldest forms, the female and male flowers 

 were promiscuously scattered over the surface of the re- 

 ceptacle. But in order to further prevent self-fertilization, 

 the male flowers matured later than the female flowers, 

 and this again necessitated first the introduction of pollen 

 from other figs, later on from figs of other crops of the 

 same tree, and later on yet from figs on different trees. 

 The differentiation as to time of maturity of the male and 

 female flowers is probably anterior to the closing of the 

 eye of the receptacle by scales. A further development 

 and differentiation took place as regards the respective 

 location of the flow'ers. The male flowers were gradually 

 made to occupy the upper part of the receptacle around 

 the eye, while the female flowers were assigned the lower 

 or bottom part of the receptacle opposite the eye. 



A further step in development was a differentiation of 

 the female flowers under the influence of the wasps which 

 had come to inhabit the flowers. Some flowers prolonged 

 their styles in order to make it impossible for the Blasto- 

 phagas to injure them by the deposition of eggs. Other 

 female flowers again shortened their styles in order to 

 facilitate the deposition of the Blastophaga eggs. The 

 stigmas of these flower became useless, graduall}^ de- 

 creased in size and changed their shape, at the same time 

 losing their receptive glands. These latter flowers are 

 the gall flowers, as we see them at the present time in 

 various fis: varieties. That the p'all flower is a decfenerated 



