LICHENS 141 



202. Usnea barbata plicata (L.) Fr. 



Lichen plicatus LINNAEUS, Fl. Suec. 1122. 1755. 



Usnea barbata plicata FRIES, L. E. 18. 1831. SOWERBY, Eng. Bot. /. 257. 



Alaska (Evans, 255 in part) ; Hot Springs, Baranof Island (Trelease, 

 1 187). New to Alaska. 



The specimen from Hot Springs is finely developed, though sterile. 

 It measures nine centimeters in length and is freely branched. 



I have found record of only one additional form, U. barbata dasypoga 

 Fr., collected by Dr. Bean at old Sitka. 



CETRARIA. 



KEY TO THE SPECIES. 



Thallus straw-colored or yellow. 



Thallus depressed, sorediate Juniperina pinastri. 



Thallus erect, more or less branched, not sorediate. 



Thallus finger-shaped, hollow arctica . 



Thallus flat, lobed. 



Margins of thallus connivent cucullata. 



Margins of thallus not connivent nivalis. 



Thallus chestnut brown ciliaris. 



Thallus variously colored. 

 Thallus erect, branching. 



Lobes of thallus connivent islandica, 



Lobes of thallus not connivent. 



Lobes of thallus narrow, freely branched islandica deliscei. 



Lobes of thallus broad, moderately branched. 



islandica platyna. 

 Thallus flat, lobed. 



Lobes of thallus narrow, elongated, channeled .fahlunensis , 



Lobes of thallus not channeled. 



Thallus ciliate on the margin, sorediate. 



stzpincola chlorophylla. 

 Thallus not ciliate on the margin. 



Thallus deeply lacunose lacunosa. 



Thallus not lacunose .glauca. 



203. Cetraria Juniperina pinastri Ach. 



Cetraria juniperina pinastri ACHARIUS, Meth. Lich. 298. 1803. HOFFM. 

 Plant. Lich. /. 7. /. i. 



Alaska (Funston, 4) ; St. Michael (Setchell) ; Cape Nome (Set- 

 chell). New to Alaska, though it has been reported from Arctic 

 America by Richardson. 



