350 THE RUSTS OF NOVA SCOTIA. FRASER. 



It was less common during the fall of 1910, only one collec- 

 tion being made. The telial stage was not found although 

 collections were made at various intervals during the fall and 

 early winter. The aecial stage, Peridermium Laricis (Kleb.) 

 Arth. & Kern, has not been collected in North America. 



MELAMP3OHELLA. Schroet. 



Aecia with peri.dium. Aeciospores with verrucose walls. 

 Uredinia with peridium. Telia effused, indehiscent. Telio- 

 spores within^ the epidermal cells, one-celled ; wall ' smooth, 

 colourless. 



But one species of this genus is found in North America. 

 Some of the species which Dietel places in this genus are 

 assigned to Hyalopsom by Arthur. 



Melampsorella Cerastii (Pers.) Schroet. 



Melampsorella elatina (Alb. & Schw.) Arth. 



0. Pycnia epiphyllous, few, scattered, punctiform, incon- 

 spicuous. 



1. Aecia from a perennial mycelium forming witches' 

 brooms ; hypophyllous, in two rows, dropping out "of leaf at 

 maturity, mostly irregularly oblong or roundish, rather large; 

 peridium colourless, soon falling away and exposing spores. 

 Aeciospores sub-globoid or ellipsoid, 15-22 by 19-27/A; wait 

 colourless, thin, closely verrucose. 



II. Uredinia amphigenous, scattered or grouped, small, 

 round, .1-.4 mm. across, orange-red when fresh, pale yellow 

 when dry; peridium hemispherical, dehiscent by a small 

 central orifice. TJrediniospores ellipsoid or obovoid, 12-18 by 

 16-30ju; walls pale yellow, rather thin, sparsely echinulate. 



III. Telia hypophyllous, on whitish or pale reddish spots. 

 Teliospores within the epidermal cells, one-celled, short- 

 cylindrical or polygonal, 13-20/x broad; wall colourless, smooth, 

 thin. 



