THE FORMATION OF HYPHAL FUSIONS 



49 



In Mile Bensaude's first mode of clamp-connexion formation the 

 two septa are formed before the hook fuses with the main hypha, 

 whereas in her second mode (Fig. 23) the two septa are formed after 

 the hook has fused with the main hypha. 



My own direct observations on the development of individual 

 clamp-connexions of Coprinus lagopus and C. sterquilinus have 

 convinced me that the two septa of a clamp-connexion in these 

 species are always formed before the hook fuses with the main 



hypha (Figs. 18 and 19, pp. 35 

 and 37) and never afterwards. 

 This conclusion is supported by 

 Harder's 1 experimental work on 

 Pholiota mutabilis : the tempo- 

 rary uninucleate condition of the 

 penultimate cell of the hyphae 

 upon which he operated was a sine 

 qua non for producing haploid 

 mycelia artificially. I am therefore 

 of the opinion that Mile Bensaude's 

 first mode of clamp-connexion 

 formation was correctly conceived 

 but that her second mode was 

 based on some artifact or a mis- 

 interpretation of her cytological 

 preparations. 



r\ 



n 



Fig. 23. — Coprinus lagopus ( = C. fime- 

 tarius of Mile Bensaude). Mile 

 Bensaude's diagram showing, from 

 left to right, four stages in her 

 supposed second mode of forma- 

 tion of a clamp-connexion. The 

 hook is represented as fusing with 

 the main hypha before the two 

 septa are formed instead of after- 

 wards (c/. Fig. 21). Copied for 

 the author by Dr. Nellie Carter. 



An account of particular observations on the formation of hypha- 

 to-hypha, hypha-to-peg and peg-to-peg fusions in the species of 

 fungi in which these fusions have been investigated by the author 

 will now be given. 



Pleurage curvicolla. — Pleurage curvicolla, a coprophilous Pyreno- 

 mycete having about 124 spores in each ascus, was the first species 

 investigated. Spores were sown in hanging drops of cleared 

 dung-agar on one day, and on the next day the mycelium thus 

 originating formed many hyphal fusions (Fig. 24). Hypha-to-hypha, 



1 K. Harder, loc. cit. 



VOL. v. 



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