130 
CUMMINGS 
having seen a specimen in the Kew Herbarium which was collected by- 
Parry and labeled as from the ‘ North Pole.’ Dr. Arnold makes no 
mention of its occurrence in Newfoundland or Labrador in his lists of 
the lichens of those regions. Neither of the St. Paul specimens shows 
apothecia, and both are only slightly pulverulent. They may possibly 
be referred to P. muscigena of Fries’ Lichenes Arctoi. 
Additional Alaska species : P. obscui-a (Ehrnb.) Nyl., listed by 
Rothrock as having been collected at Kotzebue Sound; P. obscura 
sciastra (Ach.) Nyl., and P. muscigena (Wahl.) Nyl., both 
recorded by Nylander as occurring at Port Clarence; and P. melops 
ossicola Nyl., collected on St. Lawrence Island, as recorded by Ny¬ 
lander. 
PARMELIA. 
KEY TO THE SPECIES. 
Thallus straw-colored. 
Thallus large, often isidiophorous,lobes variously divided. .conspersa. 
Thallus small, sorediate, dichotomously divided...... ambigua. 
Thallus variously colored. 
Thallus olivaceous brown. 
Lobes of thallus flat, rounded crenate..... .....olivacea. 
Lobes of thallus linear or terete. 
Palmately divided. stygia. 
Dichotomously divided. lanata. 
Thallus glaucescent or blackening. 
Thallus small, dichotomously divided, sorediate. 
a?nbigua albescens. 
Thallus large, not dichotomously divided. 
Thallus gray, sometimes with blackening borders. 
Thallus more or less reticulate, not inflated. 
Thallus whitish, sorediate. saxatilis. 
Thallus grayish, not sorediate. .saxatilis sulcata. 
Thallus not reticulate, inflated. 
Lobes of thallus wide and much inflated, not black-mar¬ 
gined . .physocles entero?norpha. 
Lobes of thallus narrow, somewhat inflated. 
Lobes of thallus not black-margined .. physodes. 
Lobes of thallus black-margined. ..physodes vittata. 
Thallus blackening all over. 
Lobes of thallus flat, broad, not inflated. 
saxatilis omphalodes. 
Lobes of thallus rounded, narrow, inflated. 
physodes obscurata. 
