LEVINE: CYTOLOGY OF HYMENOMYCETES 149 
vacuoles. Clamp connections may be seen at one or both ends of 
the cells and are very common. At this stage small concavo-con- 
vex bodies on both sides of the cross walls of the hyphae appear. 
These structures stain red with safranin and are dense, homogene- 
ous bodies. They have been interpreted by Strasburger (1884), 
Harper (1902), and others as indicating the presence of protoplas- 
mic connections between the adjacent cells. Hyphal anasto- 
moses, such as are described by R. Hartig (1885) and Meyer (1896, 
1902), are also present. 
For comparison, I have also studied the mycelium of Collybia 
velutipes, which grows rapidly in malt-beef and cherry agar. Miss 
Cool (1912) and Biffen (1899) have both studied its mycelium. 
I find that the cells of the mycelium are distinctly binucleated. 
Narrower hyphae densely filled with cytoplasm were also found 
in sections of this mycelium. The terminal portion of these fila- 
ments becomes divided into uninucleated cells which give rise to 
cylindrical uninucleated oidia similar to those described by Biffen 
for the same species and Miss Nichols (1904) for Coprinus ephem- 
erus. Clamp connections are regularly present and in thick 
sections hyphal anastomoses can be also found. 
The results thus obtained show in the germ tube and early 
stages of mycelial growth that multinucleated cells predominate 
in Pholiota praecox, while in cultures two to three days old, multi- 
nucleated, binucleated and uninucleated cells are all present. 
The multinucleated cells may belong to younger hyphae as:noted. 
In older cultures binucleated cells mainly prevail although multi- 
nucleated and uninucleated cells may be found. The origin of 
the binucleated condition is not clear, but it is very apparent 
that it appears early in the vegetative hyphae and persists through- 
out the subsequent development of the mycelium and the carpo- 
_ phore. 
The cells of the mature mycelium of Collybia velutipes are all 
binucleated and here the binucleated condition may be regarded 
as fixed for the entire subsequent development, except as in the 
case of the stipe or the pileus, where the nuclei may divide, forming 
multinucleated cells. 
Cultures of four species of Polypores obtained from the 
Association Internationale des Botanistes were also studied. The 
