1924] 
WOLPERT—FUNGI AND H-ION CONCENTRATION OF MEDIA 01 
species under consideration, however, fall into 3 groups: (1) 
those fungi which are partial to lower temperatures, as Schizo- 
phyllum commune and Polyporus adustus, (2) those that are par- 
tial to intermediate temperatures, as Pholiota adiposa, Polystictus 
versicolor, and Daedalea confragosa, and (3) those that are partial 
to higher temperatures, as Lenzites sepiaria, Pleurotus ostreatus, 
and Armillaria mellea. 
These temperature relations in culture can be correlated to 
some extent with the habitat conditions of the fungus in nature. 
Schizophyllum commune, frequently found in the early spring and 
late fall in shaded brush heaps, grows close to the damp soil and 
is surrounded by cool moist air. Polyporus adustus, often found 
in the spring and early summer months, grows most frequently 
on some shaded stump or log where proximity to the soil gives 
a moist and cool habitat. Lenzites sepiaria, one of the species 
partial to higher temperatures, grows abundantly in the southern 
states, making its appearance during the warm weather following 
the rains. For this species, Falck (709) has found that 35° C. is 
the optimum. Polystictus versicolor is often found growing on 
stumps during the late spring and early fall months. Bayliss 
(08) stated that 15? C. is the most favorable for this fungus, 
but the results obtained in this study show that there is little 
to choose between 15? C. and 25? C. It is evident that growth in 
the peptone solution is a little better at the lower temperature, 
but the results obtained from the Richards’ solution indicate 
that it will grow equally well at both temperatures. 
The peptone solution is by far the best of the different culture 
media used in these experiments. In every case the fungi show 
a marked partiality to the organic source of nitrogen, and, as 
previously mentioned, express this not only i in greatly in 
growth but also in widened P, limits and in widened optimum 
Ри zones. The Richards’ solution, on the other hand, is no 
better than the solution where peptone is the source of both 
nitrogen and carbon. With this sugar-free medium no effort 
was made to determine the limits of growth in respect to hydro- 
gen-ion concentration. Consequently, it is not possible to make 
a sharp comparison, but it is to be noted that with 2 exceptions, 
Daedalea confragosa and Pleurotus ostreatus, the fungi grow in 
