THE FORMATION OF HYPHAL FUSIONS n 



Burgeff introduced a new terminology for the phenomena which 

 he had observed. He designated : as telemorphosis 1 the induction 

 of sexual hyphae (zygophores) by action at a distance through the 

 air or a substratum ; as zygotropism 2 the growth of a ( + ) zygophore 

 and of a ( — ) zygophore toward each other until they meet ; and as 

 thigmomorphosis 3 the swelling of the ends of the ( + ) and (— ) 

 zygophores when these come into contact with one another. 



Burgeff 4 sought to explain the telemorphic, zygotropic, and 

 thigmomorphic reactions which take place between a (+) and a (— ) 

 mycelium of Mucor Mucedo and other Mucorineae by supposing 

 that they are induced by volatile, soluble, sexual substances, one 

 substance for each sex, which are excreted by the mycelia and diffuse 

 readily through air or a solid substratum from a (+) mycelium to 

 a ( — ) mycelium, and vice versa. The sexual substances, on this 

 theory, act chemomorphically 5 and chemotropically 6 and, if we wish 

 to emphasise the part which chemical substances play in the sexual 

 process, instead of employing the terms telemorphosis, thigmomor- 

 phosis, and zygotropism to designate the phenomena concerned, 

 we may speak of telechemomorphosis, 7 thigmochemomorphosis 8 and 

 chemotropism? 



According to Burgeff, 10 in heterothallic Mucorineae, e.g. Mucor 

 Mucedo, Rhizopus nigricans, etc., every growing mycelium forms its 

 sexual chemical substance not merely when confronted with a 

 mycelium of opposite sex but also when it is growing by itself. As 

 evidence supporting this statement he cites the following experi- 

 ment. Atmospheric air was passed through a tube one metre long 

 containing a (+) culture of Rhizopus nigricans and then over a ( — ) 

 culture of Mucor Mucedo, with the result that, in the M. Mucedo 

 culture, the young sporangiophores were transformed into branched 

 zygophores. Where a (+) mycelium and a (— ) mycelium of Mucor 

 Mucedo, etc., enter upon the sexual process, the telemorphic effect 



1 H. Burgeff, " Untersuchungen iiber Sexualitat und Parasitismus bei Mucorineen. 

 I," Goebel's Botanische Abhandlungen, Heft IV, 1924, p. 15. 



2 Ibid., p. 12. 3 Ibid., p. 13. 

 4 Ibid., pp. 12-13, 17, 19, 23, 63-64. 5 Ibid., p. 15. 



fi H. Kniep, Die Sexualitat der niederen Pflanzen, Jena. 1928. p. 312. 



7 H. Burgeff, he. cit., p. 15. 8 Ibid., p. 13. 



9 H. Kniep, loc. cit., p. 456. I!l H. Burgeff, he. cit.. p. 76. 



