THE RUSTS OF NOVA SCOTIA. FRASER. 



353 



3. Partial section of aecidium ofPuccin 



astum arcticum. Surface and side 



view of teliospores. 



The uredinial stage is very common on the raspberry. It 

 is not conspicuous, but can be easily recognized by examining 



the under side of the leaf. The 

 telial istage is difficult to dis- 

 tinguish, but late collections of 

 leaves affected by the uredinal 

 form usually show abundant 

 telia, when sectioned and exam- 

 ined with the microscope. 



Arthur in the "North Ameri- 

 can Flora' 7 reports this species 

 only from Alaska on Eubus 

 stellatus. Farlow (Rhodora 10: 

 13. 1908) mentions a specimen of typical P. arcticum on Eubus 

 triflorus from Grand Manan, "N. B. He also describes a 

 Pucciniastrum found on Eubus neglectus and Eubus strigosus 

 in the north-eastern United States, and regards it as a variety 

 of P. arcticum differing from the type in the markedly conical 

 shape of the peridium and prominent spines. To distinguish 

 it he gives it the name P. arcticum (Lagerh.) Tranz., Var. 

 americanum Farlow. If this separation holds good the collec- 

 tion on Eubus triflorus belongs to the species and that on 

 Eubus idaeus Var. aculeatissimus to the variety. 



Pucciniastrum Myrtilli (Schum.) Arth. 

 Pucciniastrum Vacciniorum Diet. 

 & I. Pycnia and aecia on Tsuga canadensis. 



II. Uredinia hypophyllous, scattered or somewhat grer 

 garious, small, bullate, round, long covered by the overarching 

 epidermis; peridium hemispherical, cells small, cuboidal. 

 Urediniospores obovate or ellipsoid, 13-16 by 16 24/x; wall 

 colourless, minutely and sparingly echinulate ; contents orange- 

 yellow. 



III. Telia chiefly epiphyllous. Teliospores in the 

 epidermal cells, ellipsoid or globoid, 18-23 by 20-30/x; wall 

 smooth, thin. 



