THE FORMATION OF HYPHAL FUSIONS 



19 



paper in Petri dishes. When a slide was ready for examination it 

 was removed from the damp-chamber and then the agar film was 

 covered with water and a cover-glass. The capacity for forming 

 fusions in germ-mycelia was found to be dependent on various 

 conditions. It is especially influenced by the state of nourishment 

 of the conidia used for sowing and also by the composition and 

 thickness of the substratum. 



In the following combinations Kohler observed that the two mycelia 

 did not form fusions with 

 one another, nor did they 

 exhibit signs of telemor- 

 phosis or zygotropism : 

 Sclerotinia fructi- 

 gena with Sclero- 

 tinia ci?ierea, 

 Neurospora tetra- 

 sperma (homo- 

 thallic) with N. 

 crassa (B-hap- 

 lonts), 

 Fusarium coeruleum 

 with Neurospora 

 crassa, 

 Fusarium coeruleum with Botrytis cinerea, 

 Fusarium aurantiacum with Neurospora crassa, 

 Sclerotinia fructigena with Botrytis narcissicola. 

 On the other hand telemorphosis and zygotropism, but no un- 

 doubted plasma fusions, were observed in a more or less marked 

 degree in the following combinations : 



Botrytis allii with Botrytis narcissicola, 



Neurospora crassa (B-haplont) with N. sitophila (A-haplont) 



(Fig. 7), 

 Neurospora tetrasperma (homothallic) with N. sitophila (A- 



haplont), 

 Neurospora sitophila (A-haplont) with N. tetrasperma (B-haplont), 

 Fusarium coeruleum with Fusarium sarcochroum, 

 Fusarium coeruleum with Fusarium aurantiacum, 

 Botrytis allii with Neurospora sitophila (Fig. 8), 



Fig. 8. — Result of a mixed sowing of conidia of 

 Neurospora sitophila, s, and Botrytis allii, a. 

 A hypha of B. allii has grown toward a hypha 

 of N. sitophila which has sent out an opposing 

 branch-hypha. The two have met at the place 

 marked by a cross, but have not fused with one 

 another. From Kohler's Zur Kenntnis der 

 vegetativen Anastoniosen der Pilze. 



