348 THE RUSTS OF NOVA SCOTIA. FRASER. 



The telial stage is rather common on the large-toothed 

 aspen about Pictou. It is rather rare on the more common 

 poplar, (Populus tremuloides Michx.). The uredinial stage 

 is not conspicuous but leaves, when, the telial stage appears in 

 the fall, soon turn black and are then quite conspicuous. 



Melampsora arctica Rostr. 



Uredo Eostrupiana, Arth. 



0. Pycnia amphigenous, chiefly hypophyllous, punctiform, 

 inconspicuous, honey-yellow. 



1. Aecia hypophyllous, arranged in two rows, roundish. 

 oval or oblong, pale orange-yellow, fading to colourless, socm 

 naked, pulverulent, ruptured epidermis evident, .2-. 3 by .3 -.7 

 mm. Aeciospores globoid, about 16-21/x in diameter; wall 

 thick, colourless, verrucose, contents pale yellow. 



II. ITredinia chiefly hypophyllous, scattered, round, very 

 small, orange-yellow fading to pale yellow, somewhat pulveru- 

 lent, ruptured epidermis inconspicuous. Urediniospores ellip- 

 soid or obovate, small, 14-16 by 16-20/*; wall colourless, thin, 

 uniformly and closely verrucose; paraphyses mixed with the 

 spores, smooth, about 50/n long with heads about 22/u, broad, 

 wall thickened above. 



III. Telia mostly hypophyllous, rounded or irregular, 

 scattered or often confluent, slightly elevated, reddish brown, 

 becoming dull brown, subepidermal. Teliospores prismatic or 

 oblong, 8-10 by 22-32/u; wall smooth, pale brown, thin. 



Pycnia and aecia on Abies balsamea (L.) Mill., Pictou. 



Uredinia 'and telia on fialix discolor Muhl., and 8. rostrata- 

 Richards, Pictou. 



This rust can be distinguished from M. Bigelowii by the 

 small and thin walled urediniospores. It is common, in the 

 vicinity of Pictou. Cultures by the writer during the spring 

 of 1912 showed that the aecial stage is on Abies balsamea. 

 (See Mycologia 4: 187. 1912). 



