i8 



RESEARCHES ON FUNGI 



two hyphae, as a result of mutual stimulation, make growth curva- 

 tures toward one another and grow toward one another until they 

 meet. I see no objection to the adoption of this terminology. 



In 1930, Kohler 1 published the results of a series of experiments 

 by means of which he sought to answer the question whether or not 

 vegetative hyphal fusions can be formed between mycelia belonging 

 to two different species. He chose for his material species in which 

 young mycelia derived from conidia showed a strong inclination to 

 form fusions. A sterile glass slide was dipped in melted nutrient or 



Fig. 7. — Result of a mixed sowing of conidia of Neurovjjoru 

 sitophila, s, and Neurospora crassa, c. There has been a 

 fairly strong reaction between the two species. Their 

 germ-tubes, by means of fusion-branches which have 

 grown toward one another, have initiated the process of 

 union. After contact had been established at the places 

 marked with a cross, the growth of the fusion -branches 

 ceased, their ends did not flatten out against one another, 

 and no open fusions were formed. From Kohler's Zur 

 Kcnntnis tier vegetutivcn Anastomosen >lcr 1'ilzc. 



plain agar, and the superfluous agar was allowed to drip away. 

 When the remaining film of agar had become solid, a brush was 

 dipped into water containing a mixture of conidia of two species 

 and was then drawn over the agar film. The water so added to the 

 agar film was soon absorbed by the agar. Sometimes it was necessary 

 to sow the two kinds of conidia at successive intervals of time. In 

 some of the experiments, in order to distinguish the young mycelia 

 from one another, the two sets of conidia, before being sown, were 

 treated with a mordant (1 per cent, tannin solution) and then were 

 stained with distinctive basic dyes (methyl violet, fuchsin, mala- 

 chite green, methyl green). The slides were kept on wet filter- 



1 E. Kohler, " Zur Kcnntnis der vcgctativen Anastomosen dcr Pilzc, II.," Plnnta, 

 \ii\. X, I9.30, pp. 4!>r> T>22. 



