390 THE RUSTS OF NOVA SCOTIA. FRASER. 



Triphragmium clavellosum Berk. 

 Nyssopsora clavellosa (Berk) Arthur. 

 0. Pycnia unknown, possibly not formed. 

 I & II. Aecia and telia wanting. 



III. Telia epiphyllous, rarely on stems, on circulai 

 yellowish spots about 4 mm. in diameter which may become 

 purplish, crowded, often circinate, sometimes confluent, small, 



mostly circular, about .3-.4 mm. in 

 diameter, sometimes elongate, sur- 

 rounded by the ruptured epidermis, 

 . pulverulent, black. Teliospores 



./ If three-celled, somewhat triangular or 



truncate-obovate, about 27-33/*; wall 

 dark brown, with bent spines up to 

 HA*, tips forking and recurved; 

 of Triphragmium pedicel hyaline, exceeding the spore. 



clavellosum. 



On AralM nudicamis L., Pictou, 

 "New Glasgow. 



The large black groups of telia, which are sometimes very 

 abundant on the upper surface of the leaves make this a very 

 conspicuous rust. 



GYMXOSPOUANGIUM Hertw, F. 



Aecia with well developed peridium dehiscing by longi- 

 tudinal slits. Teliospores two-celled (rarely 3-5-celled), 

 embedded in a gelatinous matrix, germ-pores usually more than 

 one in a cell and lateral. Uredinia unknown. 



The telial stage of the species of this genus as far as is 

 known infest the Cupresseae, the majority of the species 

 occurring on Juniperus. The aecial stage occurs on the tribe 

 Pomeae of the family Rosaceae. The only exception to this is 

 Gymnosporangium externum Arth. & Kern, in which the aecial 

 >tage is found on GiUenia stipulaceae (Mycologia 1 :253. 1909). 



