234 The Plant World. 



can be said to be strictb/ arctic, although mostb/ preferrin-j 

 boreal or mountanous habitats. The following is the list of 

 species, given in regional groups. 



1. Southern Coast Species, collected at Sitka, June 

 21, all in the aecial stage onlv. 



Picccinij Grossuliriae (3chum.)Ivagerh. (i^ciiiun Gros- 

 ndariae Schum.), on Ribcs laxifloriim Pursh. This is probably 

 one of the racial forms belonging to the abundant cosmopoli- 

 tan rust with telia on various species of Carex. The exact 

 status of the form must await knowledge derived from cultures. 

 vSimilar collections have been made along this coast by a number 

 of collectors. 



Puccinia Veratri Duby, on Epilobium adenocaulonliansskn. 

 This heteroecious species, cultures of which were made by 

 Tranzschel in 1908, has not before been reported north of 

 Glacier, B. C, for either aecial or telial stages, the latter being 

 on species of Veratrum. 



Aecidium sp.,on Petasiies jrigida (L.) Fries. The host was 

 determined by Mr. W. F. Wight, November, 1910. This rust 

 is seemingly identical with the aecia on Tussilago Farfara, 

 which is known to be the aecial stage of Puccinia Poaruvi, hav- 

 ing telia on species of Poa. Repeated trials by Tranzschel, 

 however, have failed to infect Peiasites officinalis by sowing 

 teliospores from Poa. This does not preclude the Alaskan rust 

 from belonging to the Poa combination, nevertheless, for the habit 

 and texture of Peiasites jrigida are much like those of Tussilago 

 Farfara, while P. officinalis is a quite dissimilar plant. Other 

 collections of the same rust have been made in Alaska on Peias- 

 ites corymbosa (R. Br.) Rydb. by J. M. Macoun at St. George 

 Island in 1891, and by C. V. Piper at Kadiak in 1904. 



2. Interior Arctic Species, collected July 17-19 at 

 Dav-son, Yukon territory, a little north of the 64th parallel 

 of latitude, and about 300 miles from the southern sea coast. 

 Dawson is close to the eastern boundary of Alaska, and less 

 than 150 miles from the Arctic Circle. Its boreal and interior 

 ( osition give the collections unusual importance, and especially 

 as these are the first rusts to be recorded for all this great in- 

 terior territorv, so far as the writer knows. 



