98 PETER OKKELBERG 



It was found that sex was alterable by removal of flowers. Re- 

 moval of female flowers caused staminate flowers to appear, and 

 the removal of staminate flowers resulted in the development of 

 female flowers. Pritchard believes that the change is probably 

 due to disturbances in nutrition. He concludes that maleness 

 and femaleness are not always fixed characters, but frequently 

 appear more like responses of the developing organism to external 

 stimuli. He thinks that facts do not support the theory that sex 

 is wholly a matter of zygotic constitution, but indicate that both 

 males and females are partially hermaphroditic. 



Certain plants which, under normal conditions are true her- 

 maphrodites, will, under other conditions, produce two kinds of 

 sexual individuals. This is true of certain mosses and ferns 

 which normally produce antheridia and archegonia on the same 

 plant, but which, by being supplied with a certain kind of nourish- 

 ment will produce only one or the other of the two kinds of germ 

 cells. Again, it has been found that under certain conditions 

 some dioecious plants may become monoecious. Wuist ('13) 

 found that Onoclea struthiopteris, which is normally dioecious, 

 could be induced to become monoecious under proper culture 

 conditions, so that the male plant preduced female organs and 

 the female plant produced male organs. Here, again, the appear- 

 ance of the organs of the opposite sex is apparently due to the 

 nutritional environment. 



e. Hermaphroditism as a result of hybridization. During the 

 last few years some interesting facts have been brought out in 

 connection with hybridization in animals and these seem to 

 throw some light upon the sex problem. Goldschmidt ('16, '17) 

 found that by crossing European and Japanese races of the gypsy- 

 moth many so-called gynandromorphs were produced. Different 

 results were obtained if the material had a different race origin. 

 The explanation of this seemed to be that the potency of the sex 

 factors differed in different races. It will be seen that this case 

 is somewhat similar to that of the frog, in which Hertwig and 

 Witschi found a racial difference as regards the tendency toward 

 juvenile hermaphroditism; but in the latter case the hermaphro- 

 ditic condition was not retained up to the adult stage. 



