OTHER METHODS OF SEX-DETERMINATION 243 



in contact with the others one by one. Certain of these 

 combinations will unite and form a secondary mycelium 

 on which ''clamp connections" develop, indicating that 

 the mycelia are of "opposite sexes." Later, fruiting 

 bodies or toadstools develop from such mycelia. On the 

 other hand, other combinations, when made, do not form 

 secondary mycelia with clamp connections, and, as a rule, 

 do not produce fruit bodies. The union is interpreted to 

 mean that the mycelia in question are of the same sex. 



AB 



ab 



Ab dB 



AB 



db 



Table 1. 



Now, when monosporous mycelia from the same strain 

 (i.e., from plants living in the same locality) are tested, 

 the results are like those in Table 1. Here, the presence of 

 clamp connections, formed after the union of two monos- 

 porous mycelia, is indicated by the + sign. Failure in this 

 respect is indicated by the — sign. In the Table the my- 

 celia fall into four groups (those belonging to the same 

 group have been brought together in the Table). The re- 

 sult is interpreted as meaning that the spores of a single 

 fruit body of the species studied, namely, Coprinus lago- 

 pus, belong to four sexual groups. 



