62 



RESEARCHES ON FUNGI 



three monosporous mycelia is shown in Volume IV, Fig. 96, 

 p. 170. 



Home spores of Coprimes lagopus were sown in a hanging drop of 

 cleared dung-agar one day, and hyphal fusions were observed being 

 formed in the mycelium on the next day. The mycelium exhibits 

 fusions of all three kinds : hypha-to-hypha, hypha-to-peg, and 

 peg-to-peg. 



The stages in one hypha-to-hypha and one hypha-to-peg fusion 

 were followed. 



In the hypha-to-hypha fusion (Fig. 36), two long lateral hyphae 

 approached one another by chance. As soon as their ends arrived 



Fig. 37. — Coprinus lagopus. Five stages in the formation of a hypha-to-peg fusion. 

 The mycelium, derived from spores sown about 30 hours previously, is haploid 

 and so does not bear clamp-connexions. A : the hypha a, already united with 

 the hypha c by a peg-to-peg fusion, is crossing over the hypha b. B : the hypha 

 a is growing back toward b. C : the hypha a has now approached near to b 

 and has caused b to send out an opposing peg. D : the hypha a and the peg 

 have grown toward one another and have met at their ends. E : the hypha a 

 and the peg produced by b have now completely fused. About three hours 

 elapsed between the stage A and the stage E. Magnification, about 860. 



within a certain distance of one another (10-15 \x), the usual tropism 

 took place : the ends of the hyphae grew almost directly toward 

 one another. Eventually the tips turned very sharply toward one 

 another, met, and fused (Fig. 36, A, B, and C). About the point of 

 fusion of the two hyphae, the compound hypha displayed a very 

 decided S-shaped twist. 



In the hypha-to-peg fusion, one younger hypha grew across an 

 older hypha almost at right angles (Fig. 37, A). Then, after growing 

 about 7-8 y. past the older hypha, the younger hypha made a growth 

 curvature back to the older hypha and induced there the formation 

 of a peg (B and C). The tips of the younger hypha and of the peg 

 eventually met and fused (D and E). This fusion took place in an 

 older part of the mycelium where the medium was much exhausted 

 and in consequence the growth in length was very slow. About 



