18 BASAL CELLS OF .lK'lMA 



degenerated; this he considered to represenl an abortive tri- 

 chogyne, in accordance with l)e liaiy's anticipation. rii<- 

 acceptance of this interpretation implies the existence of a 

 close affinity between the Uredinales and the Red Seaweeds. 



In 1!)05, Christ man published the result of his researches 

 into Phragmidium speciosum, Caeoma nitens (= Gymnoconia 

 = Puccinia Peckiana), etc. According (<> 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 

 instances 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 Tormeutillae, Arthur, q.v.), the primary uredo- 

 spores in this species replacing the secidium 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 



