412 



THE RUSTS OF NOVA SCOTIA. FRASER. 



III. Telia amphigenous, mostly on culms, sheaths and 

 infloresence, oblong or linear, often confluent, black, soon 

 naked, surrounded by the ' ruptured epidermis, pulvinate. 

 Teliospores oblong-clavate, oblong-fusiform, narrowly obovate 

 or sometimes ellipsoid, 16-22 by 22-68/s apex rounded, obtuse 

 or conical, base narrowed, sometimes rounded, usually some- 

 what constricted at the septum; wall chestnut-brown, apex 

 darker, thickened 8-lOj*, smooth; pedicel coloured, firm, usually 

 as long as the spore, sometimes short, 



Aecia on Berberis 

 vulgaris L. (cultivated), 

 Truro. 



Uredinia and telia 

 on Agropyron vulgar e 

 L., A. repens Beauv., 

 Avena sativa L., Agros- 

 tis alba L., Piotou, 

 Truro ; Hordeum juba- 

 turn L., Pictou; Secale 



Teliospores of Puccinia graminis. cereale, Truro. 



Puccinia graminis is found on a large number of grasses. 

 By infection experiments Ericksson showed that it consists of 

 a number of specialized forms, all having their aecia on the 

 barberry, but nevertheless not capable of infecting one another. 

 As a result of experiments so far conducted, the following 

 forms have been indicated: 



1. Secalis, on Rye (Secale ceveale) and other hosts. 



2. Avenae, on Oats (Avena sativa). 



3. Airae, on Airia. 



4. Agrostidis, on Agrostis. 



5. Poae, on Poa. 



6. Tritici, on Wheat (Triticum vulgar e). 



