216 



var. leucomeloides Lindsay, Trans. Linn. Soc. 27: 321. 

 1871).* 



Substrata: On the earth. 



Distribution: Not uncommon in the Boreal zone or in high 

 alpine situations (above 6,000 ft.). It occurs from 

 Labrador to Vermont, westward to Washington (Mt. 

 Rainier) and Alaska. 



Observations: This easily recognized species is found reprer 

 sented by typical material only in the most boreal or 

 alpine regions of our area. Owing to the fact that Tucker- 

 man did not recognize the species tenuifolia (= var. 

 crispa Ach.) almost all our herbaria material is determined 

 as C. islandica. This misconception I first pointed out 

 (Bryol. 16: 34. 1913) when I published a figure of the 

 Linnean type. 



ExsicCATi: No. 3. Tuck., Lich. Amer. sept. Exs. i & 2. 



1848. "Montium Alborum." = atypical. 



No. 44. Decades No. Amer. Lich., Cummings, etc. Mt. 



Moosilauke, N. H. July 30, 1892. = in some numbers 



typical material, in some atypical, in some C. tenuifolia. 



No. 6. Lich. Boreali-Amer., Cummings, etc., same as above. 



No. 6. Canadian Lich., Macoun. 



Cetraria islandica var. platyna (Ach.) Fr. 

 Synonymy: Cetraria platyna Ach., Synop. Meth. Lich. 229. 

 1814. 

 Cetraria islandica var. platyna Fr., Lich. Europ. reform. 37. 



1831. 

 Cetraria islandica a. vulgaris'^ latifolia Kremplhb., Lich. 



* "laciniae as long and flexuous as in P. leucomela." Type loc. "Greenland." 

 t Type loc, "St. Paul's Island, Behring Sea." Grig. Descript., "Thallus grow- 

 ing in tufts, erect or sub-decumbent, pallid-fuscescent brown or even nigricant 

 at the tips but paler basally, rigid but brittle, the lobes variable in width, attaining 

 to a maximum of i6 mm. and a height of 7 cent, the margins dividing into rela- 

 tively short irregularly outlined lacinulae, both major and minor axils rounded, 

 lobes commonly plane but variously contorted, only the tips canaliculate; the 

 superior surface smooth, irregularly lacunose, the lacunae shallow, or here and there 

 ribbed, scarcely differing below except in remaining pale with scattered white 

 soredia, cortex continuous, sub-shining, the borders of the lobes laciniolate- 

 spinulose. Apothecia not seen." 1. c. 



