296 ALLEN— SEX INHERITANCE IN SPH^ROCARPOS. 



reduction divisions which resuh in the formation of four spores 

 from each spore mother cell — a notion strongly suggested by pre- 

 vious investigations of dioecious liverworts and mosses. 



Spores being available in considerable numbers in my cultures, 

 it seemed worth while to attempt to determine whether the conclu- 

 sions thus arrived at for the European species hold likewise for 

 6^. DonnelUi. Spores liberated by breaking the capsule wall in a 

 drop of water were sown on soil June i6, 1916. Spores sown at 

 this time of year have been found to be relatively slow in germina- 

 tion ; the sporelings appeared during the following autumn and win- 

 ter. On March 10, 191 7, most of the plants that resulted having 

 begun to produce involucres, those that had grown from the spores 

 from two capsules were carefully examined, with the results shown 

 in Table I. As a rule, plants of a group of four could be reason- 



TABLE I. 



Sex of Plants Grown from Spores from Two Capsules of 

 Sphccrocarpos Donncllii (Culture PSC2B). 



Spore tetrads sown June 16, 1916; plants examined March 10, 1917. 



2 females, 2 males 3 groups 



2 females, i male 2 groups 



I female, 2 males i group 



1 female, i male i group 



2 females, 1 group 



2 males 3 groups 



I female, i group 



I male i group 



1 female, 2 males, i ? 3 groups 



2? I group 



4? I group 



3 females, i male, i group 



4 females, 2 males, i group 



2 females, 3 males, 2? i group 



3 females, 2 males, 3? i group 



Totals: 30 females, 32 males, 14 (?). 



ably assumed, because of their contiguity, to have come from the 

 spores of a single tetrad. Sometimes, however, the plants in a 

 group were sufficiently separated to make their relationship, though 

 probable, open to question. Isolated plants, or groups of two or 

 three, evidently indicated that one or more spores had failed to 



