Nichols—Binuclealcd Cells in Some Basidiomycetes. 33 
cleated cells just beneath the epidermis of the leaf. Each of 
these cells divides into a sterile cell above and a fertile cell below. 
The fertile cell becomes binucleated not by the division of its 
original single nucleus but by the migration through the wall 
of the nucleus of a neighboring vegetative cell of the mycelium. 
He sajte, “In the presence of the spermatia with their special 
cytological characters, etc., the only view that seems capable of 
explaining the facts is that the fertile cell was formerly fer¬ 
tilized by the spermatia, but that now the process has become 
reduced, fertilization by means of spermatia having been re¬ 
placed by the more certain method ol! fertilization by the nucleus 
of a neighboring vegetative cell. ” In view of these facts ne 
holds it to be evident ‘ 4 that the Uredineae present an alterna¬ 
tion of generations which is as sharply marked as that of the 
higher plants.” 
Since the young carpophores invariably have binucleated cells 
these must originate either at the first formation of the car¬ 
pophore or sometime during the growth of the mycelium. The 
latter hypothesis is suggested by Harper’s observations on Hy¬ 
po chnus. In order to obtain some evidence on this point the 
study of the nuclei in the mycelium of some of the Agarics was 
begun at the suggestion of Professor R. A. Harper under whose 
direction the work was carried on. 
METHODS. 
Spores were collected from a large number of Agarics in the 
following manner. Zinc racks were washed in alcohol and passed 
through a flame and then placed in plates which had been washed 
in 95 per cent, alcohol. The racks were covered with bell jars 
which were also washed in 95 per cent alcohol. Two racks were 
placed side by side under each jar. Slides were washed m 
alcohol and passed through a flame and then placed on the lower 
bars of the racks, each rack holding four. The pileus from a 
mature fruit body was carefully removed from the stipe and 
placed on the upper bars of the rack. When the basidia dis¬ 
charge their spores they fall on the slides below thus lessening 
3 
