Mosses of the Canadian Arctic Expedition, 1913-1918. 



By R. S. Williams. 



New York Bota7iical Garden, Bronx Park, New York. 



The following list enumerates 68 species of the true mosses. The genus 

 most largely represented is Drepanocladus with 11 species, all sterile; next comes 

 Bryum with 9 species, 5 of which are fruiting; all the other genera, 33 in number, 

 are represented by 1 or 2 species except Dicranum of which there are 3, one of 

 which C. elongatum is in fruit, and Stereodon which contains 4 species. 



The greatest number of species (7) separated out from one collection and 

 growing more or less intimately associated, were obtained from a piece of sod, 

 some 4 by 6 inches on the upper surface, cut out from the tundra on Barter 

 island on the coast of arctic Alaska. These seven species, all sterile and men- 

 tioned in the order of their abundance, the commonest first, are as follows : — 

 Catoscopium nigritum, Swartzia montana, Drepanocladus brevif alius, Bryum 

 neodamense, Chrysohypnum stellatum, Encalypta brevicolla and Drepanocladus 

 scorpioides. From a small collection made on Sadlerochit river about twenty- 

 five miles inland from Camden bay, Alaska, the following were separated out — 

 Bryum pallescens, Leptobryum pyriforme, Mnium affine, Drepanocladus aduncus 

 and Rhytidium rugosum; the Bryum and Leptobryum bearing fruit. 



The specimens are sterile unless otherwise stated. One species, Bryum 

 neodamense, found in Europe, from the Pyrenees to the arctic coast, does not 

 seem to have been credited before to America. Another, Drepanocladus brevi- 

 J'olius, has only been noted from Greenland, while two others are described as 

 new. 



The region collected over extends from about latitude 65° to 70° 35' N., and 

 from the northern Alaska coast eastward to about longitude 110° W., and unless 

 otherwise noted the specimens were collected by Mr. F. Johansen. 



Class Musci 



Subclass SPHAGNALES. 



Family SPHAGNACEAE. 



Genus Sphagnum (Dill.) Ehrh. 



Sphagnum subsecundum Nees. 



Tundra pond at Teller, Port Clarence, Alaska, Aug. 6, 1913. 



Sphagnum fuscum, (Sch.) H. Klinggr. 



High tundra swamp on Herschel" island, Yukon Territory, July 31, 1916. 



Subclass BRYALES. 

 Tribe ACROCARPI. 

 Family DITRICHACEAE. 

 Genus Swartzia Ehrh.; Hedw. 

 Swartzia montana (Lam.) Lindb. 



On cliffs on "Ptarmigan creek," Sadlerochit river, Alaska, Nov. 13, 1913. 

 Tundra on Barter island, Alaska, summer 1918, J. Hadley; fruiting. Tundra 

 at Bernard harbour. Northwest Territories, June, 1916. On dolomite cliffs at 

 Murray point, Victoria island. Northwest Territories, March 25, 1916. 



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