18 BASAL CELLS OF ACIDIA 
degenerated ; this he considered to represent an abortive tri- 
chogyne, in accordance with De Bary’s anticipation. The 
acceptance of this interpretation implies the existence of a 
close affinity between the Uredinales and the Red Seaweeds. 
In 1905, Christman published the result of his researches 
into Phragmidium speciosum, Caeoma nitens (= Gymnoconia 
= Puccinia Peckiana), etc. According to him, the process that 
took place was the fusion of the contents of two equal and 
similar gametes, with the exception that the nuclei remained 
side by side unfused. A considerable portion of the wall 
between the two fusing cells was broken down, and the process 
was of the nature of a conjugation, not a fertilisation. 
Blackman and Fraser (1906) next examined a number of 
other species, and in Melampsora Rostrupii they found the 
same process which Christman had observed, though they still 
considered that other species, e.g. Puccinia Poarum, showed 
instanees of the migration of a nucleus as in the first subject 
studied. 
Christman, in 1907, showed that a similar act of conjugation 
between two equal cells takes place in the formation of the 
primary uredospores of Phragmidium Potentillae-canadensis 
(= Kuehneola Tormentillae, Arthur, q.v.), the primary uredo- 
spores in this species replacing the eecidium which is absent. 
In 1908 Olive, in examining the primary uredospores of 
Triphragmium Ulmariae, tried to reconcile the difference be- 
tween these opposing views: he considered that conjugation 
took place between two cells, one larger and one smaller, and 
that either a large opening was formed so that the two proto- 
plasts fused, or a narrow hole was produced through which the 
nucleus of the smaller cell passed into the larger. He considered 
the upper sterile cell as a degenerating tip-cell, not an abortive 
trichogyne. The fusing cells might be placed in almost any 
position with respect to each other. In Puccinia transformans, 
a micro-form, possessing only teleutospores, he shows that the 
basal cells which produce them arise equally by the fusion of 
two uninucleate cells. 
Kurssanow, in 1910, investigating Puccinia (Gymnoconia) 
Peckiana, found both cases. that of Blackman and that of 
