Lichens Collected by the Canadian Arctic Expedition, 1913-18 



By G. K. Merrill, Rockland, Maine 



The Lichens collected by the Canadian Arctic Expedition of 1913-1918 

 were from points on the arctic coast along the 70th parallel. Exploration 

 extended inland from Camden bay, Alaska, for a distance of thirty miles, and 

 for about the same distance in the region of the Coppermine river. Otherwise, 

 the lichens were taken from islands adjacent to the coast, or from the mainland 

 near the sea. Rocks, beach pebbles, old bones, driftwood, and tundra formations 

 supported the coast lichens; but, on the Coppermine river, a few were from the 

 dead branches of living trees. The lichens found inland are to be considered 

 elements of a continental flora; but it remains to be established if there is a 

 distinctive strand flora. 



The terms alpine and arctic as applied to lichen distribution must ever 

 remain elastic. There are so many cosmopolites among hchen species, that the 

 flora of any continental arctic area may show the floral elements of great land 

 surfaces predominating. 



Twelve alpine or arctic lichens enumerated in the accompanying list are 

 found in the State of Maine, some of them descending to the sea level; on the 

 other hand, the list contains the names of fifty species of general distribution 

 at low altitudes in Maine and, indeed, all New England. Of the five hundred 

 and five lichens credited to the arctic by Darbishire, one hundred and ninety- 

 nine have been collected in Maine. The mean annual temperature of the Maine 

 coast varies but little from 45° Fahr. The mean for that period of the year in 

 which the sun is visible on the arctic coast should be relatively low, just how low 

 I have no means of knowing. It would seem, however, that the lichens of 

 temperate regions are less intolerant of low temperatures than are arctic and 

 alpine ones of warmth. 



Three species only of the list seem to be exclusively arctic, so far as North 

 America is concerned, namely: Cetraria chrysantha, Polyblastia scotinospora, 

 and Verrucaria striatula forma dealbata. Dactylina arctica, Duforea ramulosa, 

 Duforea madreporiformis, and a few other high northern lichens may be 

 observed on many qf our western mountains in alpine situations. The mountains 

 and general region of Alberta and British Columbia may be counted on to 

 furnish duplicates of every lichen in our list except Cetraria chrysantha, Poly- 

 blastia scotinospora, and Verrucaria striatula. 



If one may judge by the appearance of the foliaceous and, to a certain 

 extent, the fruticose material from the arctic coast, conditions have not been 

 favourable for development and growth. Infertile, dwarfed, and atypical ex- 

 hibits are almost the rule. The crustose forms, however, find conditions more 

 to their liking and well developed, fertile thalli are common and so abundant 

 that the rocks everywhere are covered. Caloplaca miniata and C. elegans are 

 everywhere profusely developed, particularly the first mentioned, and the con- 

 jecture seems warranted that the species is a pioneer. Climatic conditions are 

 unfavourable for rock disintegration or decay of any sort, and for this reason 

 crustose lichens tend to persist. It is easily conceivable that a well identified 

 plant of any crustose species might be found in its original station after the 

 lapse of one hundred years, and, in the case of those of slow growth, compara- 

 tively unaltered. In the Swiss alps, a plant of Rhizocarpon geographicum was 

 watched by three generations of observers and its diameter had increased by 



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