276 RESEARCHES ON FUNGI 



mates for the (ah) nuclei there present. Thus, proceeding away 

 from the (AB) hypha, the number of {ab) hyphae which become 

 diploidised is progressively increased. 



In the terminal cell of any elongating hypha, in which a pair of 

 conjugate nuclei has become established, cell-division accompanied 

 by conjugate nuclear division and the formation of clamp-con- 

 nexions soon sets in, and thus the number of pairs of conjugate 

 nuclei becomes increased. 



Let us now suppose that an (AB) nucleus makes its way, via a 

 bridging hypha, into the middle cell of three cells of a single (ab) 

 hypha (Fig. 145, Nos. 1-3). We may suppose that the (AB) 

 nucleus becomes conjugate with the (ab) nucleus. Then we have 

 three cells in a row, the middle cell containing a conjugate pair 

 of nuclei {AB)-\-{ab) and each of the end-cells an (ab) nucleus. The 

 diplcidisation of these two end-cells becomes effected very simply 

 (Fig. 145, Nos. 4-6). The (AB) nucleus of the middle cell divides 

 and so liberates an (AB) nucleus which travels into one of the end- 

 cells where it becomes associated with the (ab) nucleus there 

 present. Then the (AB) nucleus of the middle cell divides again 

 and so liberates a second (AB) nucleus which travels into the other 

 end-cell where it becomes associated with the (ab) nucleus there 

 present. Thus the middle cell has rapidly diploidised its two 

 neighbouring cells by a very simple process. 



Let us suppose that a diploid lateral branch of a diploidised (ab) 

 h3rpha meets and fuses with a non-terminal cell of a radial or other 

 (ab) hypha which is still in the haploid condition {cf. Fig. 148, 

 Nos. 1-3), Then we have three nuclei to consider, a conjugate 

 pair {AB)-{-{ab) in the end cell of the diploid branch-hypha and a 

 single nucleus (ab) in the non-terminal cell of the haploid hypha. 

 The diploidisation of the cell of the haploid hypha is rapidly 

 effected by the same process as that described in the last para- 

 graph : the (AB) nucleus of the conjugate pair {AB)-\-{ab) divides, 

 and thus provides an additional (AB) nucleus which moves into 

 the haploid cell and becomes associated with the (ab) nucleus there 

 present. Again, a diploid cell has diploidised a neighbouring 

 haploid cell. 



In general, as the (ab) mycelium becomes diploidised, wherever 



