Volume 14 Number 10 



The Plant World 



A Magazine of General Botany 

 OCTOBER, 1911 



SOME ALASKAN AND YUKON RUSTS. 



J. C. Arthur. 



Very little is known of the uredineous flora of Alaska. The 

 most extensive series of specimens yet reported is that made 

 by the Harriman expedition of 1899. Forty species were listed,* 

 largely collected and determined by Dr. William Trelease, 

 Director of the Missouri Botanical Garden. All but two spec- 

 ies (three collections) of the list were secured along the southern 

 border of Alaska and the Aleutian Islands. The two exceptions 

 are Puccina laurentiana Trel., on Saxijraga, and Melampsora 

 aipina Juel, with I on Saxijraga, and II (III) on Salix (the I 

 being listed as Caeoma saxijragarum) , both obtained from the 

 northern part of Bering sea. Besides this series only occa- 

 sional srecimens have come to hand in various ways, and prac- 

 tically all from along or near the southern sea-coast. 



During the summer of 1909 an extensive collecting trip was 

 made through the interior of Alaska by Prof. A. S. Hitchcock, 

 agrostologist of the U. S. Department of Agriculture. Although 

 devoting his attention primarily to the grasses, he secured a 

 few excellent specimens of rusts, which he kindly turned over 

 to the writer for stud\-. All, with two exceptions, the aecia 

 on Rihes and uredinia on Ledum, belong to species not listed 

 by Dr. Trelease in the Harriman report. Only three locahties 

 are represented by the collection, but these three localities are 

 long distances apart and are typical of as many highly distinct 

 climatic regions: the temperate region along the southern sea- 

 coast, the interior arctic region about Dawson, and the coast arctic 

 regie n near Berirg strait. Itisnoeworthy that none of the species 



♦Alaska: the Harriman Expedition 5:36-41. 1904. 



