TRANSACTIONS OF SECTION K. 775 



Upwardly progressing zone of spore discharge reaches them. Their prop function, 

 however, is retained up to tho last possiblo moment, and they disappear just in 

 time to prevent the falling spores from striking and adhering to them. 



In a number of other species of Coprinus the cystidia are removed from the 

 gills during spore discharge by a process of auto-digestion similar to that which 

 occurs in C. atramentarhis. 



2. Asexual Reproduction in a Species of Saprolegnia. 

 By A. E. Lechmere, M.Sc. 



A species of Saprolegnia was kept in pure culture in various media, but it 

 proved impossible to obtain the formation of sexual organs. It has, therefore, 

 not been possible to identify the species. The cultures were, however, of interest 

 because of the variety of methods of asexual reproduction shown by them when 

 grown under different conditions. Methods of asexual reproduction were observed 

 in this one species which were regarded by earlier authors as characterising six 

 different genera of tho family. 



3. On Pseudomitosis in Coleosporium. 

 By Professor V. H. Blackman, M.A. 



A form of nuclear division intermediate between mitosis and amitosis is to 

 be observed in the divisions of the teleutospore in Coleosporium Tnssilaginis. 

 A well-marked spindle, centrosomes, and polar radiations are present, but the 

 spireme which appears after nuclear fusion disappears again, and the chromatin 

 becomes granular. The granular material becomes arranged on the spindle, 

 and is then drawn apart towards the poles without the formation of 

 chromosomes. 



4. Chromosome Reduction in the Hymenomycetes. 

 By Harold Wager, F.R.S. 



The nucleus of tho basidium is formed by the fusion of two nuclei (Wager, 

 1892), rarely by three or four (Wager, 1893 ; Maire, 1900). The presence of six 

 or eight nuclei in a basidium as described by Rosen (1892) has not been observed, 

 but some light is thrown upon Rosen's observations by the appearances presented 

 in Mycena (jalcriculata. In this species the nuclei both of the hyphae and the 

 young basidium constantly show three or four chromatin masses in each nucleus, 

 probably chromosomes, and in some cases, especially in the basidium, where the 

 nuclear membrane is not clearly seen, we get an appearance of six to eight minute 

 deeply staining nuclei, which correspond perfectly with the description of the 

 nuclei of the fungi given at about the date of Rosen's paper by Schmitz and 

 other observers. 



The fusion of more than two nuclei in the basidium appears to be an 

 abnormal, and not a normal, occurrence, as Dangeard has maintained. 



The nuclei in the young basidium are extremely small. Previous to fusion 

 they increase much in size, and in some cases they appear to extrude a quantity 

 of chromatin, in the form of a nucleolus-like body, into the cytoplasm. 



The number of chromosomes in the vegetative nuclei appears to be four. 

 These are constantly seen in Mycena galericulata, both in the hyphae and in the 

 young basidium. After the extrusion of the chromatin the young basidial nuclei 

 show the normal structure of a resting nucleus with a faint nuclear network 

 and a nucleolus. In this stage they fuse. 



There was no direct evidence of conjugate division in the hyphae. In 

 Stropharia stercorarius it was clear that conjugate division was possible, but in 

 some other forms it was just as clear that the fusion nuclei of the basidium 

 might be sisters. 



After fusion both the basidium and its nucleus increase very much in size 

 and the cytoplasm stains intensely. The nuclear network becomes very distinct, 

 and in some cases appeared to form a nearly continuous spireme. The nuclear 

 thread breaks up into eight segments, out of which the minute deeply staining 



