294 



ALLEN— SEX INHERITANCE IN SPH^ROCARPOS. 



The sporophytes appearing in the cultures have given rise to 

 spores which were apparently normal in every respect and which 

 germinated, although thus far there has always been a considerable 

 proportion of ungerminated spores. Whether this failure of some 

 of the spores to germinate is due to a lack of viability or to a failure 

 to provide the most favorable conditions for germination is a ques- 

 tion yet to be determined. The spores of S. Donnellii in my cul- 



Sphccrocarpos texanus. Living female (Fig. 7) and male (Fig. 8) plants 

 from greenhouse cultures. Rhizoids not shown. Drawings by Miss Martha 

 Engel. X 7- 



tures invariably remain united in tetrads (Fig. 11), even to a time 

 when the capsule wall, calyptra, and surrounding involucre have 

 completely broken down and the spores consequently are being 

 scattered.^ Such a persistent union of the spores is characteristic, 

 as is well known, of other species of Sphcurocarpos, but not, accord- 

 ing to Miss Haynes (1910), of 5*. Donnellii as found in nature. 



The Sex Ratio in Sph^rocarpos. 



C. Douin (1909) investigated the sex of the respective members 

 of groups of the thalli of Sphccrocarpos, the members of each group 

 having resulted presumably from the germination of the spores of 

 a tetrad. His observations showed that, at least as a general rule, 



1 Since this was written, it has been observed in one culture, containing 

 numerous sporoph^^tes, that the tetrad walls had largel.v broken down, allow- 

 ing the spores to become separated from one another. 



