Mains : Heteroecism of Puccinia 



321 



1919, Mr. G; R. Hoerner sent a collection of aecia on Hydro- 

 phyllum obtained at Corvallis, Oregon. Aeciospores from this 

 collection were sown, obtaining infection upon Ely mas virginicus. 

 with a slight development on Elymus canadensis and Triticum 

 aestivum, both of the latter, however, proving not to be congenial 

 hosts. A study of the Elymus virginicus material showed that it 

 agreed with the other material of P. apocrypta. 



Discussion 



The foregoing work, while by no means settling the complete 

 aecial relationships of these rusts, has resulted in a realignment of 

 them, which, it is felt, is more in keeping with their morphology. 

 Puccinia montanensis, so long as it was considered as having its 

 aecia on Hydrophyllum, invited comparison with such species as 

 Puccinia bromina Erikss. on Bromus and P. secalina Grove (P. 

 dispersa) on rye, both of which have their aecia on the closely 

 allied family, Boraginaceae. From both of these species P. mon- 

 tanensis is distinguished, among other characters, by possessing 

 abundant paraphyses in the uredinium, these being practically lack- 

 ing in both P. bromina and P. secalina. Puccinia montanensis 

 with aecia on Bcrberis, however, invites comparison with other 

 species of rust with long-covered telia having aecia on species of 

 the Berberidaceae. Such species are Puccinia Koeleriae in North 

 America with aecia on Mahonia Aquifolium and Puccinia Arrhena- 

 theri in Europe with aecia on Berbcris vulgaris. Both the latter 

 rusts agree with Puccinia montanensis in possessing abundant para- 

 physes in the uredinium. In Puccinia apocrypta, on the other 

 hand, having Hydrophyllum for its aecial host, we have a rust 

 which with its lack of paraphyses, at least, agrees with P. bromina 

 and P. secalina. It is true that P. apocrypta differs from both of 

 the latter in its smaller urediniospores with lighter colored walls, 

 but similar differences can be found in the grass rusts among those 

 having species of Ranunculaceae for their aecial hosts. 



It is difficult, of course, to say what other species may serve as 

 aecial hosts for the above rusts besides those shown by culture. It 

 would appear that Puccinia montanensis consists of several races, 

 one of which goes to Bcrberis Fcndlcri. It is not possible at the 



