318 



Mycologia 



with an abundance of thin-walled, peripheral paraphyses (fig. 2), 

 giving the sori a fringed appearance under the binocular. The 



Fig. 2. Urediniospore, uredinial paraphyses and teliospores of P. mon- 

 tatiensis obtained from culture of Aecidium Fendleri on Hystrix Hystrix (X 

 400). 



urediniospores are 19-26 by 21-34 fx and have brown walls and 

 8-10 scattered germ pores. The teliospores are broad, 18-34 by 

 35-64 fj, (fig. 2), and have rather thick walls. 



On the other hand, a comparison of the above material with that 

 resulting from the cultures with Hydro phy Hum aecia mentioned 

 above (Arthur 1. c. 4) showed points of marked difference. The 

 uredinia and telia connected with the Hydrophyllum aecia are scat- 

 tered or loosely grouped. The uredinia are yellow and without 

 paraphyses. The urediniospores are 13-21 by 19-25 fi and have 

 pale yellow or colorless walls with 6-8 scattered germ pores. The 

 teliospores are narrow, 13-23 by 32-48 /x, with thin walls except 

 for the apical thickening (fig. 3). On the basis of the above cul- 



Fig. 3. Urediniospores and teliospores of P. apocrypta on Elymus vir- 



tures, therefore, Berberis Fendleri must be considered as the only 

 proven aecial host of this rust. That other aecial hosts exist is a 

 possibility. The geographic distribution of P. montanensis, as 

 indicated by specimens in the herbarium, is British Columbia, Wis- 



ginicus obtained by culture with aeciospores from Hydrophyllum capitatum 

 ( X 400). 



