THE RUSTS OF NOVA SCOTIA — FKASER. 437 



U. mimhilis (Peck) Arthur, and U. Atl-insonii Magn., have 

 their aecial stages on Ahies halsamea (L.) Mill. The aecia 

 are the white spored forms that have passed as Peridermium 

 halsameum Peck. 



The question arises whether these are distinct species with 

 like aecia or only one species that has been regarded as distinct 

 on account of minor differences. The experiments as far as 

 (hey went tended to show that the species established are good 

 or at least are races of the same species. 



The following European species has also been recognized 

 since the paper was revised. It adds a new species to the 

 American flora. The determination was made by Dr. J, C. 

 Arthur. 



Puccinia karelica Tranz. 



0. I, Pycnia and aecia in Trientalis americana (Pers.) 

 Pursh. Pictou, June 20, 1912. 



II & III. Uredinia and telia in Carex paupercuJa Michx., 

 Pictou, Folleigh Lake. 



isroTE. 



The following additional sj^ecies were collected after the 

 preceding paper was in type. 



Hyalopsora* 



Cycle of development not understood; telia and two other 

 spore forms known, called aecia and uredinia; aecia and 

 uredinia sub-epidermal, telia within the epidermal cells. 



Hyalopsora Aspidiotus (Peck) Magn. 



I. Aecia amphigenous, rounded, small, yellow, tardily 

 dehiscent. Aeciospores ellipsoid or polyhedral, large, 30-40 by 

 40-50^; wall thick 2.5-3.5/^, colorless, verrucose. 



II. Uredinia amphigenous, irregularly scattered, round, 

 small, golden-yellow, somewhat pulverulent; peridium delicate. 



