LEVINE: CYTOLOGY oF HYMENOMYCETES 163 
however, are not generally accepted, and his figures are incon- 
clusive. My own studies on the nature of the clamps and hyphal 
fusions are not conclusive, on this point. As described above, I 
have observed clamp connections and hyphal anastomoses in 
cultures three days old, but nothing that would clearly indicate 
nuclear migrations, though in some cases I have found empty cells 
adjacent to binucleated cells. 
It is well established that the binucleated cells do not arise as 
carpophore initials. They are present long before the carpophores 
appear and the stimuli leading to the production of the-latter 
seem to be vegetative and environmental. 
In order to bring out clearly the stages at which binucleated 
sporophytic cells are found I have tabulated all the available data 
as to the number of nuclei in the cells of the mycelia, rhizomorphs, 
carpophores, etc., of the Basidiomycetes so far studied. Twenty- 
seven species have been described as having regularly binucleated 
cells in their mycelia and rhizomorphs. The data show rather 
clearly that the binucleated condition does not originate at any 
definite point but may arise anywhere in the mycelium. The germ 
tubes (PL. 4, FIG. I, 2) are generally multinucleated. The young 
mycelium has multinucleated cells (PL. 4, FIG. 3, 4) although bi- 
nucleated and uninucleated cells are also found. Miss Nichols 
does not believe that there are conjugate divisions in the germ 
tube but positive observations as to the occurrence of conjugate 
divisions are sadly lacking. As noted above, I have found no 
case of conjugate division in the material I studied. 
As shown in the table, oidia and chlamydospores are reported 
by Istvanffi (1895), Biffen (1899), Maire (1902), and Nichols 
(1904), for many forms. I have studied such asexual spores on 
the mycelia of Collybia velutipes. The evidence seems to be 
that these spores are usually uninucleated and it would seem 
natural that the mycelia from which they arise should consist 
of uninucleated cells. Such spores are certainly not so common 
in the Basidiomycetes as they are in the Ascomycetes. They 
probably should be regarded as the asexual reproductive bodies 
of a gametophyte stage. As yet no binucleated spores from 
binucleated hyphal cells like the uredospores of the rusts have 
been found in the rumen 
