Co 



RESEARCHES ON FUNGI 



succeeded in observing the formation of three hypha-to-peg fusions 

 and one peg-to-peg fusion. 



In two of the hypha-to-peg fusions, a younger lateral hypha at 

 first by chance approached the side of an older hypha at an oblique 

 angle (Fig. 34, A) ; as soon as it had arrived within a distance of 

 about 15 [x from the older hypha, it changed its direction of growth 

 and began to grow directly toward the older hypha (B) ; as soon as 

 its apex had arrived within about 3-4 y. of the older hypha, the latter 

 emitted a small opposing peg (C) ; the lateral hypha and peg then 



Fig. 34. — Coprinus sterquilinus. Five stages in the formation of a hypha-to- 

 peg fusion. A : the hypha a, by chance, is growing very obliquely toward 

 the hypha b. B : a, having come sufficiently near to the side of b, has 

 become tropically stimulated by b and is now growing directly toward b. 

 C : the hypha a, now much nearer to the hypha b, has stimulated b mor- 

 phogenically so that b has formed a peg opposite to the end of a. D : the 

 ends of the hypha a and of the peg have grown toward one another 

 and have met. E : the hypha a and the peg produced by b have now 

 completely fused. About 15 minutes elapsed between the stages B and E. 

 Magnification, 434. 



grew slightly in length until their tips met (D) ; and, finally, com- 

 plete fusion took place (E). All these stages in the process of hyphal 

 fusion were completed within half an hour. In a third hypha-to-peg 

 fusion, the peg was longer and had already appeared when a lateral 

 lvypha was seen approaching it. Complete fusion in this instance 

 took place forty minutes after the beginning of the observations. 



In the peg-to-peg fusion (Fig. 35), two older hyphae running 

 more or less parallel to one another emitted a pair of pegs opposite 

 to one another. The pegs grew toward one another and fused in 

 the usual manner. 



No hypha-to-hypha fusion was seen becoming established, but 

 an examination of an older mycelium enabled me to conclude that 



