116 FROMME: SEXUAL FUSIONS IN FLAX RUST 
pecially striking were the cases found in Puccinia Cirsii-lanceolatt. 
Fifteen nuclei in a single cell were figured in one instance. From 
his study of Triphragmium and other forms, Olive concludes 
that only one of the gametes ordinarily bears a sterile cell and that 
one gamete generally lies somewhat below the other. This leads 
him to believe that the two gametes differ somewhat in the time of 
their development. The first hyphae to form the upright layer 
under the epidermis do not fuse among themselves but cut off 
sterile cells and are fertilized by the tip cells of hyphae that push 
up later from below. Olive does not differentiate these cells as 
“fertile and vegetative,’’ as Blackman has done, but believes they 
are entirely equal in size and contents and differ only in time of 
development. He agrees with Christman that the sterile cells 
are merely “buffers” and cannot be considered phylogenetically 
as trichogynes. : 
In two shorter articles, published earlier in the same year (08), 
Olive calls attention to the similarity between the multinucleated 
cells, which he found at the base of a number of young aecidium 
cups, and the archicarps of De Bary, Massee, and Richards. He 
thinks it quite probable that the basal cells of the aecidium are the 
ultimate branches of these multinucleated cells. The cup type of 
aecidium was probably derived from the more simple caeoma type. 
He has found as many as six nuclei in a fusion cell of the caeoma 
type, due probably to nuclear division proceeding faster than cell 
division, and points out that a still further development of such 
a cell coupled with partial suppression of other neighboring cell- 
fusions, especially in a deep lying caeoma, might give rise to the 
cupshaped type of aecidium. 
Kurssanow (10) reinvestigated Puccinia Peckiana (Caeoma 
nitens of Christman and Gymnoconia interstitialis of Olive). He 
agrees with Christman in all essentials. The conjugation is 
between entirely similar gametes. Sterile cells are normally 
formed from both conjugate cells, but these have degenerated or 
have been lifted off by the rupture of the epidermis before the time 
of fusion. These are mere “buffer” cells and cannot be inter- 
preted as trichogynes. Kurssanow does not accept Olive’s 
attempt to harmonize the observations of Blackman and Christ- 
man. Either the two methods of conjugation are limited to the 
