300 ALLEN— SEX INHERITANCE IN SPH^ROCARPOS. 



additional sporelings are still occasionally appearing. However, 

 the slowness of germination has given opportunity for the entrance 

 of blue-green algae, whose presence in quantity either checks further 

 germination or results in the death of the young sporelings while 

 very minute. The germinations observed in this series have re- 

 sulted as follows : 



In 12 pots, I female sporeling; 



In 4 pots, I male sporeling ; 



In I pot, I of undetermined sex; 



In I pot, I female followed by i female ; 



In I pot, I male followed by one male, and this by one of undeter- 

 mined sex (the latter possibly, though apparently not, a regenerated 

 shoot) ; 



In I pot, 2 males appearing nearly or quite simultaneously ; 



In I pot, I female followed by 2 of undetermined sex. 



Thus in 14 cases a female-producfng spore seems to have been 

 first to germinate ; in 6 cases, a male-producing spore. While too 

 fragmentary to furnish a basis for a conclusion, these figures sug- 

 gest that there may be a difiference in rate of germination in favor 

 of the female-producing spores. 



The Chromosomes of Sph^rocarpos. 



SphcErocarpos suggested itself as a favorable plant in which to 

 look for a possible chromosome difference between the sexes, both 

 because of its marked sexual dimorphism and because of the strong 

 evidence of a relation between chromosome reduction and the sepa- 

 ration of sex potentialities. So far as published records show, the 

 only previous attempt to study the chromosomes of SpJiccrocarpos 

 was by Strasburger (1909), who reports that neither in the nuclear 

 divisions in the spore mother cell nor in the structure of the nuclei 

 formed by these divisions did he find any evidence of the separation 

 of structures that could be interpreted as the bases of sex differ- 

 entiation. 



In April, 1914, through the courtesy of Professor Mangin and 

 of M. Capus of the Museum d'histoire naturelle of Paris, I was 

 enabled to locate living plants of Sphcrrocarpos (probably of 5". 

 Michelii) in the neighborhood of Bois-le-Roi. Some of this mate- 



