202 MYCOLO&Y 



repens, Elymns arenarius, Bromus secalimis and others; (3) f. sp. 

 avencB on oats and Avena elqtior, Dactylis glomerata, Alopecurus praten- 

 sis, Milium efusum, etc.; (4) f. sp. po(B on Foa compressa and P. praten- 

 sis; (5) f. sp. airce on Aira ccBspitosa and A. hottnica; (6) f. sp. agrostis on 

 Agrostis canina and A. stolonijera. 



Brown Rust of Rye, Puccinia dispersa, with its cluster cups on 

 Anchusa arvensis and A. officinalis. 



Crown Rust of Oats, Puccinia coronifera, with its secium on the 

 buckthorn, Rhamnus cathartica. Of this species there are eight 



Fig. 7 1 . — A-C, Gymnoconia interstitialis. A , ^cidia on leaf of Rubus canadensis; 

 B, piece of leaf enlarged; C, teliospore; D, teliospore oi Sphenospora pallida, 500/ i. 

 {After Dieiel: Die naturlichen Pflanzenfamilien I. lA**, p. 70.) 



speciahzed forms, as follows: (i) f. sp. avencB on oats; (2) f. sp. alope- 

 curi on Alopecurus pratensis; (3) f. sp. festuccd on Festucas; (4) f. sp. 

 lolii on rye grass, Lolium perenne; (5) f. sp. glycericB on Glyceria aqua- 

 tica; (6) f. sp. agropyri on Agropyron repens; (7) f. sp. epigm on Cala- 

 magrostis epigeios; (8) f. sp. hold on Holcus lanatus. 



Crown Rust of Grasses, Puccinia coronata, with its aecium on Rham- 

 nus frangula. Three special forms of this rust are known: (i) f. sp. 

 calamagrostis on Calamagrostis ariindinacea; (2) f. sp. phalaridis on 



1 Arthur, J. C. and Kern, F. D.: North American Species of Peridermium, 

 Bull. Torr. Bot. Club, 33: 403-43''^i iyo6. 



