LICHENS 137 



Family USNEACE^. 

 ALECTORIA. 



KEY TO THE SPECIES. 



Thallus straw-colored. 



Not blackening at the tips. 



Divaricately branched ......................................... ochroleuca. 



Densely intertangled ........................... ochroleuca sarmentosa. 



Blackening at the tips. 



Branches rounded .................................... ochroleuca rigida . 



Branches flattened ................................ ochroleuca circinata . 



Thallus variously colored. 



Thallus light brown ............................................... nlgricans. 



Thallus chestnut-colored or blackish-brown. 



Thallus robust, tips forked .................................... divergens. 



Thallus slender, tips not forked. 



Thallus paler at the ends ............................. Jubata bicolor. 



Thallus all the same color. 



Thallus pendulous ........................................... Jubata . 



Thallus prostrate or subpendulous.....y#&zta chalybeiformis . 



190. Alectoria ochroleuca (Ehrh.) Nyl. 



Beytr. 3: 82. 1788. 

 Alectoria ochroleuca NYLANDER, Prod. 47. 1857. 

 Usnea ochroleuca HOFFMANN, PI. Lich. a. /. 26. f. 2. 



Unalaska (Setchell) . Nylander reports its occurrence on St. Law- 

 rence Island and at Port Clarence ; Hooker and Arnott credit it to 

 Kotzebue Sound, under the synonym Cornicularia ochroleuca Ach., 

 and Babington to the same locality, under the synonym Evernia 

 ochroleuca Fries. 



191. Alectoria ochroleuca rigida (Vill.) Fr. 



Lichen rigidus VILLARS, Dauph. 3: 938. 1789. 



Alectoria ochroleuca rigida FRIES, Lich. Arct. 27. 1860. SOWERBY, Eng. 

 Bot. /. 2374. 



Alaska (Evans, 428) ; Orca (Trelease, 1202); Kadiak (Trelease, 

 1189). All sterile. 



Intermixed with these specimens are fragments of Alectoria jubata, 

 Sphcerophorus, and various mosses. This is an alpine and arctic 

 species. Collected at Taku by Dr. Hayes, and at Seward Peninsula 

 by Arthur J. Collier. 



