PREFACE 



In Volume IV of this work it was shown that a diploid mycelium 

 (Ab) J r (aB) of Coprinus lagopus will not only diploidise a haploid 

 mycelium (aB) or (.46) in what was called a legitimate combination, 

 but will also diploidise a haploid mycelium (AB) or (ab) in what 

 was called an illegitimate combination. How diploidisation in an 

 illegitimate combination of a diploid and a haploid mycelium is 

 accomplished I was unable to explain. Recently, however, in a 

 review of Volume IV, Felix Rawitscher 1 has suggested what 

 seems to be a very simple solution of the problem. According 

 to him, during the diploidisation process in both of the illegiti- 

 mate combinations (AB) X (Ab)+(aB) and (ab) X (Ab)-\-(aB) the 

 haploid mycelium receives from the diploid mycelium both (.46) 

 nuclei and (aB) nuclei. These nuclei pass out of the diploid myce- 

 lium into the haploid mycelium, divide there conjugately, displace 

 the (AB) or (ab) nuclei of the (AB) or (ab) mycelium, and take 

 possession of the growing hyphae. Later on, when the transformed 

 (AB) or (ab) mycelium produces a fruit-body, in each young basidium 

 an (Ab) nucleus fuses with an (aB) nucleus and thus makes it possible 

 for the fruit-body to produce (as was found by me) all the four kinds 

 of spores : (AB), (ab), (Ab), and (aB). 



Another explanation of illegitimate diploidisation has just been 

 offered by Quintanilha. 2 He has suggested that, when a haploid 

 mycelium (Ab) is mated with a diploid mycelium (AB)+(ab), under 

 the influence of an (.46) nucleus the two nuclei of a conjugate pair 

 (AB)A-(ab), whilst dividing parallel to, and close to, one another, 



1 F. Rawitscher, Zeitschrift fur Botanik, 1933, p. 136. 



2 A. Quintanilha, " Le probleme de la sexualite chez les Champignons. Re- 

 cherches sur le genre Coprinus," Bol. da Soc. Brot., II ser., Vol. VIII, Coimbra. 



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