Studies in Polyporus_frondosus FR

Abstract

Polyporus frondosus is of wide geographic distribution, occuring frequently on the deciduous, although rarely the conifoerus, trees in many parts of the world.
In Japan this fungus occures in the deciduous, and commonly attacks Quercus crispula and Castanea crenata. It is weli known that Polyporus frondosus is a good edible mushroom not only in Europe, but olso in Japan.
In the present paper the writer deals with the results of the morphological, physiological and ecological investigations and then wishes to make a comparative study on the two strains, black (sporophores are blackish) and white (sporophores are whitish), of this fungus.
(1) Sporophores of this fungus occure in autumn on the old trunks, the exposed roots, the stumps and on the soil near the host plants.
(2) The slightly different features of the sporophores between the two strains are as follows:
(a) Colour of the upper surface of the pileus,
(b) form and size of the pores of the pileus,
(c) character of the flesh,
but there is no remarkable difference in the size of the basidiospores. The length and width of the basidiospores, of Polyporus frondosus
based on 100 spores from each of three different materials are as following table:
_??_
(3) The germination of the basidiospores of this fungus is found on 2 per cent glucose agar at 32°C. Before putting forth the germ-tubes they swell considerably.
(4) The mycelium of this fungus develops vigorously on six artificial culture media, especially on Bouilon-glycerin agar, SAITO's onion-soy agar and potato-glucose agar, but very feebly on PIEPER-HUMPHREY's synthetic culture medium and CZAPECK's solution agar.
On the culture media, the writer can not find remarkable differences in the macroscopic appearances between the two strains, but slightly on SAITOS onion-soy agar and CZAPECK's solution agar.
The chlamydospores and chlamydosporelike bodies are formed on the culture media. They are elliptical, spherical and 10_??_17μ×12_??_35μ in size.
(5) The favorable temperature for the mycelial growth of this fungus seems to be from 10°C to 35°C with an optimum of 26_??_30°C.
(6) The result of the laboratory tests on the durability of four species of wood against Polyporus frondosus showes that the heartwood of Pinus densiflora and Castanea crenata is much resistant to decay.
The sapwood proves to be far less resistant to decay than the heartwood. In three culture strains of this fungus, the black (Iwate) strain seems to be the most active organism.
(7) According to the writers observation, Polyporus frondosus causes a white or white spongy Iot in the oaks in late stage of decay.
(8) The mycclium of this fungus formed so-called BAVENDAMM'S “Oxydationszonen” on Potato-glucose media containing low concentration of gallic or tannic acid. The discolouration caused by the black strain is somewhat severer than that by the white strain.
(9) The writer has made some efforts to produce a fruit body of this fungus on the saw-dust medium, but never gained matured one.
The results of the studies above mentioned show that there are two strains, black and white, in. Polyporus frondosus, but the differences between them are not remarkable.