748 SUMMARY OF CURRENT RESEARCHES RELATING TO 



a dense cytoplasmic mass appears at the end, changes into a prominent 

 aster, and aids in the formation of the nuclear membrane ; this centro- 

 sphere-like body Kusano proposes to call the " karyodennatoplast." 

 After repeated nuclear divisions, the cytoplasm divides into polyhedral 

 masses, which become multinucleate sporangia, each one giving rise to 

 200 to 300 swarm-spores. 



Nuclear Phenomena in Pyronema confluens.* — W. H. Brown gives 

 a preliminary note of hfs investigation of a form of Pyronema, which 

 agrees outwardly with P. confluens, as investigated by Harper, but differs 

 in the behaviour of the nuclear fusions. Brown suggests that he may 

 be dealing with a variety or form of Harper's fungus. Trichogynes and 

 antheridia were formed in it, but they were never in contact, and the 

 nuclei of the antheridia degenerated. No fusion of nuclei occurred 

 either in the ascogonium or ascogenous hyphaj, except in the binucleate 

 cell which forms the ascus. He also finds that there is only one reduc- 

 tion in the ascus — it occurs in the first division of the primary ascus 

 nucleus, when there is what appears to be a synapsis and a split spireme, 

 followed by the passing of four or five chromosomes to each pole. 



Sexuality and Development of the Ascocarp in Ascophanus car- 

 neus.j — E. M. Cutting gives an account of the systematic position of 

 this fungus, then describes his methods of securing the plant, and of 

 preparing the microscopic sections. He also describes his experiments in 

 the germination of the spores ; he was unable to induce growth further 

 than the production of germ-tubes. The cells of the vegetative mycelium 

 are multinucleate ; the nuclei are minute, and seem to divide karyokinetic- 

 ally. There is a pore in the middle of the transverse wall of each cell, 

 and on either side of the pore a number of granules are situated. A 

 pore is also present in the ascogonial cells. One ascogonium gives rise to 

 the fruit. The archicarp is a " solecite " composed of a varying number 

 of cells, either simply curved, or twisted in a complicated manner. There 

 is no male organ ; the apical portion of the archicarp may possibly re- 

 present the trichogyne. The middle portion functions as an asco- 

 gonium, and the cells composing it seem to be multinucleate at their 

 formation ; fusion between nuclei seems to take place in all the cells ; 

 there is no nuclear migration from one cell to another. All the asco- 

 gonial cells have the power of giving off ascogenous hyphte ; the tips 

 bend over in the usual manner, and the ascus is formed from the pen- 

 ultimate cell. Cutting regards the fusion of nuclei in the ascogonial 

 cells as a reduced type of fertilization in which the female nuclei fuse in 

 pairs. He is of opinion that the genus Ascophanus presents many 

 points of similarity with Ascobolus and Lasiobolus, and ought to be 

 retained in the Ascobolaceae. A full bibliography completes the paper. 



Nuclear Division in the Ascus. J — A. Gruillierrnond challenges the 

 results obtained by Fraser and Welsford in their work on the cytology 

 of the ascus. He denies the occurrence of the second reduction which 



* Johns Hopkins Univ. Circular, No. 6 (1909) pp. 42-5. 

 t Ann. Bot., xxiii. (3909) pp. 399-417 (1 pi.). 

 j Comptes Rendus, cxlix. (1909) pp. 350-2. 



