2i6 RESEARCHES ON FUNGI 



around its periphery, are reproduced in Figs. 125, 126, and 127, 

 respectively. 



The data for, and the results of, the eight pairings are embodied 

 in Table II. In the eighth column is shown the number of hours 

 taken after inoculation for the complete diploidisation of each of the 

 large central haploid mycelia. In the ninth column is shown the 

 distance in mm. travelled by the nuclei through the large haploid 

 mycelium. This distance was measured from the centre of the 

 inoculum through the centre of the large haploid mycelium to the 

 haploid mycelium's periphery. 



By making use of the time and distance data given in columns 

 eight and nine in Table II, the average speed of the nuclei derived 

 from the inoculum when passing through the large central haploid 

 mycelium and diploidising it could be very simply calculated and, 

 as shown in the last two columns of the Table, this speed varied in 

 individual experiments from 0-79 mm. per hour to 1-18 mm. per 

 hour. 



It is known from the experimental and cytological work of 

 Lehfeldt ^ that, in Typhula erythropus, when two haploid myceha 

 of opposite sex unite and make a hyphal fusion, a nucleus passes 

 from one of the mycelia into the other and makes its way along the 

 mycelium which it has entered. During its passage, it divides and 

 its progeny divide repeatedly, and the nuclei thus produced by 

 successive nuclear divisions pass along the hyphae and scatter 

 through the mycelium, the hyphal septa breaking down before them 

 to permit their passage. Finally, at a number of points on the 

 mycelium now containing both kinds of nuclei, the nuclei become 

 associated in pairs and clamp-connexions begin to be formed, 

 especially at the ends of the leading hyphae which are rapidly 

 growing in length. It is owing to this division and movement of 

 nuclei which enter a haploid myceUum when it comes into Qontact 

 with another haploid mycelium of opposite sex that, in the end^ 

 any haploid mycelium when mated with another haploid mycehum 

 becomes converted into a diploid mycehum. It is on the assumption 

 that, during its diploidisation, a haploid mycelium of Coprinus 



^ W. Lehfeldt, " tJber die Entstehung des Paarkernmyzels bei heterothallischen 

 Basidiomyzeten," Hedwigta, Bd. LXIV, 1923, pp. 13-51. 



