Holden and Harper—Nuclear Phenomena. 65 
are not sister nuclei. The upper of the two cells then repeats 
the process of division, hut this time the cell divides unequally. 
The lower cell is much smaller and is cut off obliquely. The 
upper cell, resulting from this latter division, is destined to be 
an aecidiospore, while the lower is sterile and ultimately dis¬ 
appears. The lower cell, resulting from the first division, con¬ 
tinues to cut off cells above. Each of these cells, in turn, cuts 
off a sterile cell. There is thus formed a row of cells, the al¬ 
ternate members of which are sterile. The disappearance of 
the sterile cells, leaves a row of fertile cells, the aecidiospores, 
each containing two nuclei. Ultimately the epidermis is rup¬ 
tured and the spores are free for dispersion. Sappin-Trouffy 
(1) and Poirault and Eacihorski (3) have described the for¬ 
mation of the teleutospore and its germination to the promycel¬ 
ium in Coleosporium. The two accounts agree in general 
The teleutospore is cut off from the mycelium, in a, manner sim¬ 
ilar to that of the first cell in the aecidiospore series. It thus 
contains from, the start two nuclei, which soon place themselves 
close together and fuse (Eig. 1). The teleutospore then in¬ 
creases in size to about four times its former dimensions and 
thus becomes a promycelium. Uuclear and cell division fol¬ 
low, resulting in a row of four uninucleated cells. Erom each 
of these cells a sterigma grows out toward the surface of the 
sorus. When the tube emerges on the surface of the sorus, its 
end expands and the nucleus and cytoplasm flow into the en¬ 
larged part, which is set free as a sporidium. 
The process of conjugate division as described by Poirault 
and Eacihorski involves some very unusual features when com¬ 
pared with the nuclear divisions in other fungi and must cer¬ 
tainly be further investigated before the results of these authors 
can he accepted. 
The most normal division they have observed is in the teleu¬ 
tospore. In one instance they found an anaphase with four 
centrosomes and finely striated protoplasm in the equatorial re¬ 
gion. The division of the fusion nucleus in the promycelium 
of Coleosporium Euphrasiae is described as follows^ The nu¬ 
cleus is provided with a network of thickset fibers and a single 
nucleole with a large central vacoule. This stage lasts for a 
5 
