Mycologisclies Centralblatt, Bd. I, Heft 9. 
Ausgegeben am 15. September 1912. 
Some recent work on the cytology of fungus 
reproduction. I. 
By J. RAMSBOTTOM, 
Assistant, Department of Botany, British Museum. 
(Schluß.) 
In the Pyrenomycetineae Winge (1911) has published a paper 
under the very appropriate title ‘‘Encore le Sphaerotheca Castagnei ”. de 
Bary (1863) was the first to find what he considered to be the sexual 
organs in this species. Two erect protuberances arise simultaneously 
from different branches; one of these branches is the unicellular ascogonium 
and the other consists of two cells, the terminal one of which is the 
antheridial cell. The antheridial branch is always closely applied to the 
ascogonium. Much controversy took place concerning whether a true 
fertilisation occurred or not. In 1895 Harper worked at the species with 
modern cytological methods. He announced that the antheridium and 
ascogonium are both uninucleate and that when the antheridial cell 
becomes closely applied to the ascogonium, the walls between the two 
organs break down to allow the male nucleus to pass into the ascogonium 
and fuse with the female nucleus. Dangeard (1897) denied that there 
was ever any open communication between the cells. He often found two 
nuclei at a later stage in the ascogonium but these he held arose by a 
division of the ascogonial nucleus probably by amitosis. Blackman and 
Fraser (1905), while preparing some slides of Sphaerotheca Castagnei 
for class purposes, came across stages which seemed to prove the correctness 
of Harpers views, and published a short note with figures to that effect. 
Winge states that Dangeard’s interpretation is the correct one and restates 
many of the latters arguments. He criticises Harper’s figures, saying 
that they represent all the nuclei as being globular, whereas this is only 
true for the male nucleus. The principal points of his paper are as 
follows: The ascogonium seems to have an attraction for the antheridial 
branch, probably as a reminiscence of former times still emitting a sub¬ 
stance which attracts the antheridium. No fusion was ever observed 
between the two cells; they are always separated by a gelatinous layer 
formed by the walls of the two organs. At a later stage two nuclei 
occur in the ascogonium. These are usually of different sizes. The 
smaller nucleus has a similar structure to the larger one, and it is obvious 
that they have arisen from the division of the original ascogonial nucleus, 
although, unfortunately, this division has not been seen. Very often at 
the stage when two nuclei are present in the ascogonium one finds the 
remains of the degenerated male nucleus in the antheridium, and several 
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