THE FORMATION OF HYPHAL FUSIONS 



57 



At j in Fig. 102, A, of Volume IV (p. 178) of this work are shown 

 two peg-to-peg fusions of P. anserina and to the right of them two 

 pegs facing one another but not yet fused. The two peg-to-peg 

 fusions were correctly called bridging hyphae ; but, at the time the 

 drawing was made, I was unaware that a bridging hypha is a product 

 of the fusion cf two pegs. 



Fimetaria fimicola. — The same types of hyphal fusions can be 

 observed in the mycelium of this fungus as in the species of Pleurage 

 already treated of. A hanging drop of cleared dung-agar was 

 inoculated with some mycelium from a stock culture, and next day 

 hyphal fusions were produced in the mycelium in considerable 



Fig. 32. — Fimetaria fimicola. — Three stages in the formation of a hypha-to- 

 peg fusion. A : the hypha a, which is slender, happens to be approach- 

 ing perpendicularly the hypha b, which is stout, septate and vacuolate. 

 B : in response to a stimulus given out by a, b has put out an opposing 

 peg : and now the hypha a and the peg are just coming into contact 

 with one another. C : the hypha a and the peg produced by the 

 hypha b have completely fused. Magnification, 434. 



numbers. Some peg-to-peg fusions are illustrated at o, p, q, and 

 between the hyphae d and e in the next Chapter in Fig. 59 (p. 105). 



Only in one instance, a hypha-to-peg fusion, were stages in the 

 process of fusion observed : a slender hypha, full of protoplasm, 

 grew directly toward the side of a thick hypha which was septate 

 and vacuolated (Fig. 32, A). As soon as the slender hypha had 

 approached within about 10 [i of the thick hypha, the latter put out 

 a small opposing peg. The slender hypha and the peg then met 

 and fused (B and C). 



All stages in peg-to-peg fusions were found in various parts of 

 the mycelium, but lack of time prevented ray observing the .actual 

 fusion of any particular pair of pegs. 



Pyronema confluens. — This well-known Discomycete can readily 

 lie cultivated from spores which, after having been shot on to 

 cleared dung-agar, begin to germinate in about 4-5 hours. The 



