88 



development of conidia-fruits and a long extension of conidia-bearing hyphae. 

 Thus it produced white conidia-fruits on the 12th day, which coloured dirty 

 brown on the 25th ; the length of conidia-bearing hyphae gave 4 mm. The 

 diameters of conidia-fruits varied from 0.15 to 0.7 mm. A 10% -culture 

 formed white conidia on the 16th day, which changed to dirty brown on the 

 27th. Conidia-fruits were long-stalked and rather scatteringly developed. 

 They were small in general, but mixed with some large ones, their diameters 

 varying 0.25-0.57 mm. In a 15% -culture white conidia-fruits first appeared 

 on the 18th day and ripened on the 34th. The formation of conidia- 

 bearing hyphae was very much reduced, showing only a scanty local develop- 

 ment, so that the greater part of the mycelium remained entirely naked. 

 The size of conidia-fruits themselves diminished beyond measure : 0.2 mm 

 in diameter. In a 20% -culture the reduction of the reproductive organs 

 went so far that I could see no trace of them even after nine months. 

 A similar result was observed by Bachmann 1 ) in Thamnidium elegant, 

 whose spore-formation was quite suppressed, when cultivated in a strong 

 solution of malt-extract. Schostakowitsch 2 ) also found that Dematium 

 reared in a concentrated solution of cane or grape-sugar produced only sterile 

 mycelium. 



d. Potassium nitrate. — In a 5% -culture white conidia were formed 

 on the 7th day and changed to black after two days more. This early 

 blackening was noticeable also in the case of potassium chloride. The 

 length of conidia-bearing hyphae was" 1.7 mm and the diameter of conidia- 

 fruits 0.4 mm. A 15% -culture produced white conidia-fruits on the 9th 

 day, which blackened on the 14th. A 20% -culture was distinguished by 

 a remarkable diminution of the size of the sexual organs : i.e. conidia-fruits 

 1.3 mm thick, conidia-bearing hyphae 1 mm long. 



e. Potassium sulphate. — All cultures prospered well. Both 5% and 

 10% -cultures formed white conidia on the 7th day, which were tinged 

 dirty brown after five days more. Conidia-fruits 0.8 mm thick, conidia- 

 bearing hyphae 3.8 mm long. 



If we compare the three salts of potassium — chloride, bromide and 

 iodide — we reach the conclusion, that chloride mostly promotes the formation 

 of conidia, next followed bromide and then iodide. As to the colour of 

 conidia-fruits chloride of 5% or stronger causes the blackening, while bromide 

 and iodide let it remain dirty brown through all cultures. 



*) J. Bachmann. Joe tit. S. 129. 



2 ) W. Schostakowitsch. Ueber die Eedingnngen der Conidienbildung bei Kuss- 

 thaupilzen. Flora. 1895. Bd. LXXXI. S. 393. 



