Black : The imbedded ANTiiERiDruM in Drvopterts 559 



continuation of the prothalliuni as a cylindrical process. This 

 process continues as a leaf or bears upon it leaves, roots, and 

 ramenta. Sporophytic growths occur also on prothallia without 

 the intervention of a cylindrical process, or as tracheids in the 

 prothalliuni or cylindrical process. Sporangia also were observed 

 to occur on the process. 



Quite recently a paper has been published by Yamanouchi 

 ('08, III) on apogamy in Nephrodium. This details an account of 

 an embryo produced apogamously, with the gametophytic or x 

 number of chromosomes. The writer in his previous papers on 

 Sporogenesis and on Spermatogenesis, Oogenesis, and Fertiliza- 

 tion in Neplirodiiim showed that under ordinary conditions the life 

 history of this fern was quite orthodox. Under somewhat arti- 

 ficial cultural conditions, e. g.^ keeping the prothallia rather dry 

 and exposed to bright sunlight, watering only from below^, fertili- 

 zation was prevented. According to Yamanouchi the prothallia 

 grown under such conditions developed slowly with larger cells 

 than those grown under normal conditions. Antheridia were pro- 

 duced in abundance with active sperms, to all appearances capable 

 of fertilizing an egg-cell, and reacting positively to 0.0 1 per cent, 

 solution of sodium malate {Joe. cit. 298). The rarely found arch- 

 egonia were seen to be in a collapsed or poorly developed condi- 



r 



tion, probably incapable of functioning. The development of the 

 sporophytic outgrowth was observed to be simultaneous with the 

 growth of the archegonial cushion and to originate from a super- 

 ficial cell in this region, in connection with cells just below it. 

 No micrration or fusion of nuclei was observed. The cells that 

 comprise the apogamous embryo are distinguished from the cells 

 of the prothallium by their smaller size, their relatively larger 

 nuclei and denser cytoplasm. There is described here an embryo 

 with the gametophytic number of chromosomes, arising from a 



V 



single superficial cell and the vegetative cells beneath it, differing 

 only in appearance from a normal embryo by the absence of the 

 foot. This is the first case recorded of an apogamous embryo 

 with the alleged gametophytic number of chromosomes. 



During the autumn of 1908 several fine specimens of a south- 

 ern fern,* Dryopteris stipidaris (Willd.) Maxon, which were being 



**The original specimen was brought from Cuba by Prof. C. H. Eigenmann. 



