THE GYN.ECOCENTRIC THEORY. 1 83 



plants, and some observers claim to have found that the receptive 

 cells are of slightly larger size, or in other words, that the incipient 

 female is better developed than the male. Whether such differ- 

 ences in size of male and female plants have been observed in 

 higher unisexual, filamentous algae, where heterogamy prevails, 

 as in Qidogoiiiuiu, the writer is not prepared to state, but doubts 

 not that here the female plant is likewise the better developed. 



Passing to the Bryophytes (mosses and hepatics), where there 

 is an undoubted alternation of generations, we find that the 

 adult sexual shoot in mosses is often unisexual ( though arising 

 from an embryonic form, the protonema, which often gives 

 shoots of both sexes), and it is a matter of observation in many 

 mosses that the female shoot is larger and stronger than the 

 male. Whether there are instances in which the male moss plant 

 is as well developed as the female, we must leave to the taxonomic 

 bryologist to decide, but the fact is well established that, when 

 the sexual leafy plants are unisexual, the female is commonly 

 stronger than the male. In the lower members of the Bryoph}tes, 

 the hepatics, the unisexual condition is not so frequently found 

 as in mosses, but in Marchaiitia po/yinorpha and some species of 

 Riccia and Prcissia which have unisexual gametophytes, the bet- 

 ter developed female gametophyte obtains as in the mosses. Of 

 course the better development of the female plant in such in- 

 stances is related to higher nutrition required for egg-production, 

 and to the supporting of the sporophyte, either entirely or in part, 

 while the male plant escapes this work of support, which is in a 

 sense a caring for offspring. 



In the Pteridophytes unisexual gametophytes are more com- 

 mon than among the Bryophytes, and wherever the sexes are dis- 

 tinct, the female is better developed than the male, whether 

 among the homosporous members or among the heterosporous. 

 In our common ferns, the homosporous leptosporangiates, the 

 sex may be governed to some extent in the laboratory, as the 

 writer has done in Asplcniitiu, by sowing some spores on clay 

 and others from the same plant on black soil ; those on the clay 

 gave rise to small males and those on the black soil to similar 

 males ( where crowded ) and, where not so much crowded, to 



