LICHENS 145 



212. Cetraria islandica delisei (Boiy.) Schaer. 



Cetraria delisei BoRY in Schaerer, Enum. 16. 1850. 



Cetraria islandica delisei Schaerer, Enum. 16. 1850. — Westr. Faergh. /. 

 16 c. 



Hall Island (Trelease, 1197) ; St. Matthew Island (Trelease, 1195, 

 1205); St. Lawrence Island (Trelease, 1196); Plover Bay, Siberia 

 (Trelease, 1199); Cape Nome (Setchell). Recorded by Farlow as 

 having been collected on the expedition to Point Barrow ; J. M. Ma- 

 coun collected it on St. Paul Island ; Nylander credits it to St. 

 Lawrence Island. 



It is noticeable that the development of the marginal fibrils is very 

 slight in the variety delisei. No. 1205 from St. Matthew Island 

 shows a few fibrils on the finer branches, near the apex of the fronds. 

 All these forms are somewhat coarser than those of the variety de- 

 lisei in the Tuckerman Herbarium, and all are sterile. With the 

 specimen from Hall Island is a species of Dicranum. 



213. Cetraria islandica platyna (Ach.) Th. Fr. 



Cetraria platyna AcnARivs, Syn. 229. 1814. 



Cetraria islandica platyna T'o.. Fries, Lich. Arct. 35. i860. 



Hall Island (Trelease, 1201, 1202); St. Lawrence Island (Tre- 

 lease, 1200) ; Plover Bay, Siberia (Trelease, 1203). New to the 

 Alaska region. 



The specimens of this variety have a much richer chestnut color 

 than the type, while the surface of the thallus is very highly polished 

 and the marginal fibrils are very slightly developed. Not mentioned 

 in Tuckerman's Synopsis of N. A. Lichens, but given by Fries as 

 occurring in Greenland. 



214. Cetraria arctica (Hook.) Tuck. 



Dufourea arctica Hooker in Richards. , Frank!. Narr. 762, append. 47. /. j/. 



1823. 

 C<?/rar?a anr/zVa Tuckerman, Syn. N. A. L. i: 30. 1882. 



Locality lost (Trelease, 1236) ; St. Matthew Island (Coville and 

 Kearney, 2117a) ; Plover Bay, Siberia (Trelease, 1237; Coville and 

 Kearney, 1850). Sterile. Reported by Farlow as occurring at Point 

 Barrow; collected by Macoun on St. Paul Island, and by Dr. Hayes at 

 Taku. Hooker and Arnott report it from Kotzebue Sound under the 

 synonym Dufourea arctica Br., and Nylander records its occurrence 

 at Port Clarence and on St. Lawrence Island under the synonym Dac- 

 tylina arctica (Hook.). 



Mixed with it are Cetraria islandica and various mosses. 



