62 BOTANICAL GAZETTE [JANUARY 
of its normal environment in order that germination might be 
effected. 
Coprinus comatus, Boletus sp., and a few other forms failed 
also to germinate on filtrates or decoctions of the soil in which 
the plants grew. The soil filtrate cultures were of course swarm- 
ing with the bacteria which would thrive under such conditions. 
Equally futile have been the attempts to germinate these spores 
in the presence of alkaline substances, in a slightly acid medium, 
or in the presence of a reducing agent. Hartig* mentions the 
germination of Merulius lacrimans in the presence of ammonium 
and other alkaline compounds, after the failure of many other 
substances. 
Brefeld® found that Zil/etia caries fails to germinate in 
nutrient solution. If already germinated in water and then 
transferred to nutrient solution the death and bursting of the 
promycelium soon occurs. 
DILUTION OF FOOD MATERIALS. 
Concerning the minimum food supply necessary for more or 
less perfect germination there seem to be almost no references 
in the literature. The concentration, however, at which some 
substances begin to attract chemotropically, or practically this 
lower concentration, has been determined by Miyoshi.*° For 
example, cane sugar at 0.01 per cent. attracted the hyphae of Mucor 
stolonifer, and ammonium nitrate attracted the same fungus at 
0.05 per cent.; while meat extract of 0.005 per cent. was attractive 
for Saprolegnia. On the other hand, Eschenhagen* and others 
have found that germination and growth of the mold fungi may 
occur at very high concentrations. 
Examining horizontal lines in table VII, these experiments 
are more or less comparable from the point of view of the con- 
centrations of the medium. The standard nutrient salt solution 
7 HARTIG, R.: Der echte Hausschwamm. 
*° BREFELD, O.: Vgl. Unters. a. d. Gesammtgebeit der Mykologie. Part V, p. 152- 
»® MIYOSHE, M.: Ueber Chemotropismus der Pilze. Bot. Zeit. 52: 1-28. 1894- 
% ESCHENHAGEN, F.: Ueber den Einfluss von Lésungen verschiedener Concen- 
tration auf das Wachstum von Schimmelpilzen. Inaug.-Dissertation, Leipzig. 1889- 





