19 14] FROMME—AECIDIUM CUP 31 



ument than Endo. Semp 



sim 



argument 



Sempervivi as further proof of the primitive 



mycelium 



mycelium seems to me 



highly specialized condition. A more desirable relation from the 

 standpoint of the continued welfare of the fungus is difficult to 

 conceive. The fungus thus becomes independent of the chance 

 association of hosts for its propagation. A decrease in the number 

 of spore forms is perhaps to be expected with the increased effi- 

 ciency of the perennial mode of life. The necessity for the pro- 

 duction of resting spores is done away with, as well as the 

 production of repeating spores for extensive propagation. A 



mycelium 



of the short-cycled 



micro-forms, for example P. fusca and P. Adoxae, and it seems 



be 



primitrv 



efficien 



gametophytic mycelium may 



maintained the supremacy and these micro-forms 



have persisted as such. 



The remarkable cases of correlation between the teleutosporei 

 of certain micro-forms and those of certain eu-heteroecious forms 

 that have been cited by Fisher (ii) and others are certainly strong 

 evidence of a phylogenetic relation between the two groups 



mor 



many 



many of the problems 



lopment of such types. The most 



seems to me 



am 



gards the micro 



forms as the most primitive forms, from 



and eu-forms have been derived by the lengthening of the sporo- 

 phyte generation and the intercalation of aecidiospores and uredo- 

 spores. 



This work was conducted under the direction of Professor R. A. 

 Harper, to whom I am indebted for many helpful suggestions and 

 criticisms. 



