1908] YAMANOUCHI— APOGAMY IN NEPHRODIUM 295 



taining the principle stated in his paper on parthenogenesis in Eual- 

 chemilla (66) , that the asexual development of an embryo from the 

 gametophyte with the diploid number of chromosomes, whether the 

 embryo comes from an egg or a vegetative cell, should be regarded 

 as apogamy; while the term parthenogenesis should be reserved for 

 the asexual development of an egg with the haploid number of chromo- 

 somes and consequently capable of being fertilized. Winkler (76) 

 opposed Strasburger's view concerning the application of the terms 

 apogamy and parthenogenesis. The difference of opinion concerns 

 not only the question of terminology, but also involves theoretical 

 views regarding the significance of the number of chromosomes, 

 which will be considered later. 



The present investigation on apogamy in Nephrodium molle 

 Desv. was undertaken in the hope of adding something to our knowl- 

 edge concerning the cytological interpretation of the phenomenon of 

 apogamy. As was stated in the preliminary note, the writer was 

 convinced of the necessity of understanding beforehand the nuclear 

 conditions throughout the whole normal life-history of this species. 

 Consequently, first sporogenesis, and second spermatogenesis, oogene- 

 sis, and fertilization were studied. These results were published in 

 two preceding papers (81, 82). 



Material and methods 



All of the apogamous prothallia used in this investigation were 

 raised from ordinary spores, secured from the same material used for 

 the study of sporogenesis, which was collected from the greenhouses of 

 the Hull Botanical Laboratory, of Lincoln Park, and of Washington 

 Park, Chicago. 



Spores were sown upon sterilized soil consisting of a mixture of 

 vegetable mold and sand, placed in the greenhouse, and kept grow- 

 ing with special care since October 1906. Some of the prothallia 

 presented certain peculiarities, one being different from the rest in 

 the same pots, but in general the differences held no relation to 

 apogamous development. Antheridia and archegonia were pro- 

 duced in profusion. Nuclear conditions in the vegetative cells, as 

 well as in spermatogenesis, oogenesis, and fertilization, were studied 



