EFFECT OF DIPLOID ON HAPLOID MYCELIA 245 



came into contact. The combinations which were investigated 

 were the following : 



A haploid mycelium with another haploid mycelium. 



(AB) X {A'B'), (AB) X {ab), (AB) x (^6), (AB) x (aB). 

 (ab) X {a'b'), {ab) x (Ab), (ab) x {aB). 

 {Ab) X {A'b'), {Ab) X {aB). 

 {aB) X {a'B'). 

 A haploid mycelium with a diploid mycelium. 

 {AB) X {AB)+{ab), {AB) x {Ab)+{aB), 

 {ab) X {AB)+{ab), {ab) x {Ab)+{aB), 

 {Ab) X {AB)+{ab), {Ab) x {Ab)-}-{aB), 

 {aB) X {AB)+{ab), {aB) x {Ab)+{aB). 

 A diploid mycelium with another diploid mycelium. 



{AB)-{-{ab) X {A'B')+{a'b'), {AB)+{ab) x {Ab)-^{aB), 

 {Ab)+{aB) X {A'b') -{-{a'B'). 

 In every one of the twenty-one pairings just indicated hyphal 

 fusions were observed in the junction zone between the two mycelia. 

 There is no reason to suppose that, if the other forty-five of the 

 possible sixty-six combinations had been investigated, hyphal 

 fusions would have been foimd lacking in them ; and we may 

 conclude from the observations actually made that, in general, in 

 Coprinus lagopus, any mycehum can form hyphal fusions with any 

 other mycelium. 



A camera-lucida drawing showing the union of a diploid mycelium 

 {Ab)-{-{aB) with a haploid mj^celium {Ab) is rej^roduced in Fig. 135. 

 The Diploidisation of a Haploid Mycelium by a Theoretically 

 Incompatible Diploid Mycelium. — In the experiments hitherto 

 described it has been shown that : (1) the haploid mycelia {AB) 

 and {ab) can both be diploidised by the diploid mycelium {AB)'^{ab) ; 

 and (2) the haploid mycelia {Ab) and {aB) can both be diploidised 

 by the diploid mycelium {Ab)-\-{aB). 

 In all the combinations : 



{AB) X {AB)+{ab), 



{ab) X {AB) + {ab), 



{Ab) X {Ab)+{aB), 



{aB) X {Ab)+{aB), 



since the diploid mycelium contains nuclei of a sex opposite to that 



