19"] CURRENT LITERATURE 85 



larger cells become multinucleate. The nuclear divisions are mitotic through- 

 out. The antheridia in all cases are uninucleate. In the forms with exogenous 

 antheridia the uninucleate spermatia arise as branchlike outgrowths from the 

 antheridia. It is probable that the antheridial nucleus divides repeatedly to 

 furnish nuclei for the successively formed spermatia. In the forms with 

 endogenous antheridia, the antheridial nucleus divides and the sperm nucleus 

 is pushed out by the spindle fibers toward the opening of the antheridium 

 through which the spermatia are discharged. The spermatia consist of the 

 relatively large nucleus, apparently surrounded by only a little cytoplasm, 

 and the protoplasmic membrane. The antheridial nucleus divides repeatedly 

 to form successive sperm nuclei which are ejected by the spindle fibers in the 

 peculiar manner described. 



The origin of the binucleate state of the carpogenic cell was made out 

 only in Laboulbenia chaetophora, which has no antheridia. In the other forms 

 neither the entrance of the sperm nucleus into the trichogyne nor its migration 

 through the trichophoric cell has been observed. In Laboulbenia chaetophora 

 the nuclei of the trichophoric and the carpogenic cells divide, and one nucleus 

 from each pair ultimately constitutes a member of the pair in the carpogenic 

 cell. From the carpogenic cell the ascogonium and ascogenous cells are formed 

 after a series of conjugate nuclear divisions. Asci bud off directly from the 

 binucleate ascogenous cells. The subsequent processes of nuclear fusion in 

 the ascus and spore formation differ in no essential detail from the analogous 



processes among the Ascomycetes with which the Laboulbeniales are usually 

 classed. 



The conclusion drawn by the author from the cytological study of the 

 Laboulbeniales is that they belong to the Ascomycetes, and more particularly, 

 on account of the possession of a perithecium, to the Pyrenomycetes. The 

 phenomena occurring in the ascus appear to lend some support to this classi- 

 fication, but the author's attempt to homologize the perithecium of the Laboul- 

 beniales with that of the Pyrenomycetes would seem to need further support. 

 Thus far the unique development of the perithecium of the Laboulbeniales 

 has no known analogies among the Ascomycetes.— H. Hasselbring. 



Sexuality 



sexu 



a comparison of a dioicous species, Br yum caespiticium, with a number of synoi- 

 cous species, chief among which is Amblystegium serpens. In the dioicous 

 species one-half of the spores give rise to protonemata which produce antheridial 

 plants, the other half produce archegonial plants. Fertilization produces a 

 bisexual sporophyte and the sex characters are separated in the reduction divi- 

 sion. Consequently two members of the tetrad are always male and two 

 female, as has actually been shown in Sphaerocarpus. In synoicous forms the 



27 Marchal, El., La sexualite chez les Mousses. Bull. Soc. Roy. Belgique 47: 

 277-285. 1911. 



