'Hi Gates, Tetraploid Mutants and Chromosome Mechanisms. 



Table I. contd. 



The Marchals in the year previous to Strasburger's paper 

 (1909) published a second paper on experimental apospory in the 

 Mosses, in which among other things, it was shown that the tetra- 

 ploid races possessed proportionally larger nuclei and cells, 

 accompanied by larger dimensions of certain organs, particularly 

 the sex organs. In a third important paper (1911) these authors 

 reach further interesting conclusions, some of which may be refer- 

 red to here. It was found that in the sporophyte of Amblystegium 

 serpens bivalens, produced aposporously by wounding the capsule 

 of the moss, the chromosomes were in groups of four ("bi-gemini"). 

 As a result of extensive experiments with many mosses, it was 

 found that in the dioecious species, regeneration of the gametophyte 

 from the sporophyte gives rise to diploid gametophytes, which are 

 physiologically bisexual, but sterile; while in monoecious species 

 a diploid gametophyte is produced which has normal sexuality and 



only thrum flowers. Self-sterility obviously accounts for the failure of the original 

 P. kcwensis to set seed. 



