THE FLORA OF SITKA, ALASKA 481 



f'romyces carophyllinus (Schrank.) Wint. 



II, III — On Dianthus carophyllus L. (186). This rust de- 

 veloped rather sparingly on the common greenhouse car- 

 nation. 



Puccinia acuminata Peck. 



Ill — On Cornus canadensis L. (58). This rust forms dense, 

 black, circular spots on the under surface of the leaf, 1 to 

 2 mm. in diameter. Infect inn is not general, hut it is 

 abundant in places. 

 Puccinia circaea Pers. 



On Circaea alpina L. (203). Common wherever the host is 

 found. 

 Puccinia epilobii-tetragoni (DC.) "Whit. 



I — On Epilobium affine Bong. (59). Common on young 

 plants shortly after starting growth in the spring. 



Puccinia grossulariae (Schum.) Lagerh. This species is by all 

 odds our most abundant and destructive species of rust. 

 Forms and I occur on species of Ribes while forms II 

 and III infect species of sedges belonging to the genus 

 Carex. Of the fourteen species of Ribes growing on the 

 Experiment station grounds in 1915, exactly one-half were 

 affected. The different species differ very much in the de- 

 gree of infection, as is noted under the remarks on each. 



On Ribes alpiniim (65). This host suffered a rather mod- 

 erate infection, in both 1914 and 1915. 



On Ribes bracteosum Dougl. (60). This species seems to suf- 

 fer quite severely when exposed to infection from nearby 

 sources of Carex, but plants growing in the forest away 

 from sources of infection are nearly or entirely free. 



On Ribes lacustre (Pers.) Poir. (61). This seems to be the 

 most susceptible species of all. In 1914, the infection was 

 severe indeed. In 1915, control measures were largely suc- 

 cessful. 



On Ribes laxiflorwm Pursh. (63). The writer has observed 

 plants of this species along the edge of the Muskeg where 

 Carex stygia was abundant, so badly infected that they lost 

 most of their leaves while a few rods away the infection was 

 moderate to light. 

 31 



