Notes on Recent Literature. 
76 
determining the orientation of the fusing cells. He considers that 
this difficulty, coupled with variability in size of the conjugating 
pore is sufficient to account for the divergence of what may be 
called respectively the Blackman and Christman method of 
binucleate origin. Olive makes mention of a case in which a 
Blackman “ nuclear migration ” is found adjacent to a “cell fusion” 
of Christman’s method. Blackman, however, in his paper of 1904 
speaks of a distinct difference in size between the migrating nuclei 
and the nuclei of the cells he considers female cells; nor does the 
determination of the orientation of the cells seem to be in doubt. 
It is of considerable interest that Olive has determined the 
exact place of origin of the binucleate condition in the Micro¬ 
form, Pucinnia transformans, to be in the basal cells, which gives 
rise, almost immediately, to teleutospores. Nevertheless, it is 
known that in certain Micro-forms the binucleate condition arises 
much earlier, for Blackman 1 found that the general vegetative 
mycelium of Pucinnia Adoxce and Uromyces Scillarium shewed 
conjugate nuclei. 
In the same paper Olive makes mention of the occurrence of 
multinucleate cells at the base of certain young aecidia of the type 
possessing a pseudoperidium. Cells containing more than two 
nuclei have been described by Blackman as occurring in the young 
aecidia of Puccinia poarum. yEcidiospores of other species pos¬ 
sessing several nuclei are of fairly common occurrence. In the 
young aecidium of Puccinia Cirsii-laneolati, Olive describes cells 
containing as many as twelve to fifteen nuclei, and in one case he 
describes twelve nuclei of one cell as undergoing division simul¬ 
taneously. He is inclined to think these cells are sporophytic 
structures and considers that they have an important bearing 
upon the mode of development of the aecidium cup. Further 
details of the origin and subsequent history of these multinucleate 
cells will be looked forward to with interest. 
Olive’s interpretation of the sexual phenomena at the base of 
the Caeoma-type of aecidium is the same as that of Christman. 
Thus he considers the cells which fuse to be undifferentiated 
gametes. Christman considers the spermatia to be asexual gameto- 
phytic spores, while Olive practically leaves them out of considera¬ 
tion altogether. It seems somewhat extraordinary that cells, which, 
as Blackman has pointed out, have the cytological characteristics of 
male gametes, should be dismissed in this way. The similarity 
between the spermogonia and certain Ascomycetes and those of 
the Uredineae merits further consideration than it has yet received. 
If the spermatia are really functionless male-cells, one can under¬ 
stand the frequent occurrence of spermogonia immediately prior to 
the formation of the primary uredo pustules of Brachy-forms 
which as we have seen are to be brought into line with the aecidia 
of other species. F.T.B. 
1 Blackman, V. H. and Fraser, Miss H. C. I., Further studies 
in the sexuality of the Uredineae. Annals of Botany, 1906. 
