230 RESEARCHES ON FUNGI 



by noting the mode of branching of the hyphae and the presence 



Fig. 130. — Coprinus lagopus. Method of determining the haploid or diploid 

 state of various parts of a large haploid mycelium which has just become 

 diploidised by a small diploid inoculum. A haploid mycelium {ab) was 

 allowed to grow in a Petri dish on dung-agar until it had attained a 

 diameter of 5-2 cm. It was then inoculated at its periphery with a 

 minute fragment of a diploid mycelium [AB)^{ah), with the result 

 that it became diploidised in less than three days. A few hours after 

 clamp-connexions had been seen all around its periphery, a piece of the 

 mycelium -covered agar, shaped like the hub of a wheel with eight spokes, 

 was cut out and divided into nine separate pieces which were set down 

 on fresh dung-agar in a Petri dish, at a little distance apart but in 

 their original order, as shown in the illustration. Hyphae grew out 

 from each of the nine pieces into the dung-agar, as indicated, and after 

 two days they were examined with the microscope. The part or parts 

 of each piece which yielded diploid (clamp-connexion-bearing) hyphae 

 have been cross-hatched and the part or parts which yielded haploid 

 hyphae have been dotted. It will be seen that a considerable inner part 

 of the original mycelium must have been still in the haploid condition 

 when diploidisation of all the peripheral hyphae had just been effected. 

 Reduced to two-thirds the natural size. 



or absence of clamp-connexions, that: (1) the central piece of 



