126 Best : Revision of the North American 



.7 mm. wide ; exothecial cells roundish quadrate to oblong, thick- 

 walled ; teeth of exostome well developed, yellowish, strongly 

 lamellate, confluent at base ; endostomial band nearly one half the 

 length of the teeth ; segments as long as teeth, more or less open ; 

 cilia 1-3, nodose, scarcely appendiculate ; annulus of two rows of 

 large cells, deciduous in pieces; operculum short, conic, obtuse; 

 spores smooth, .009-.012 mm.; matures in late winter or early 

 spring ; grows on rocks, roots of trees and on the ground. 



From Mt. Washington, New Hampshire (Allen, James), north 

 through Newfoundland (Waghorne), New Brunswick (Moser), 

 Labrador (Waghorne) to Greenland (Fl. Gr.) ; and from Montana 

 (Williams) northwestward. Idaho (Leiberg, Roll); Hector, Rocky 

 Mts. (Macoun). Found in fruit by R. S. Williams and John 

 Moser. Of wide range but rare and local.* 



Exsiccati : Macoun Can. Muse, 660 and 687 as H. dimor- 

 phuni. 



Macoun, N. F. Mosses 6 as H\ dimorphum. 



Illustrations : Dixon & Jameson Hand-Book Brit. Mosses 

 //. 50. 



Husnot Muse. Gal., pi. 8y. 



Limpricht Die Laubmoose 2 : §17. fig. jjo. 



H. sqtiarrosulum varies considerably from differences in habitat. 

 When appearing on rocks at high altitudes the tufts are usually 

 more compact, the secondary stems and branches subjulaceous 

 and the leaves more obtuse. Growing on roots of trees or on the 

 ground it is more diffuse, the secondary stems not so closely 

 branched and the leaves looser and more acuminate. The sub- 

 central papillae are good diagnostic characters. European bry- 

 ologists include under H. squarrosutum a moss, probably a dis- 

 tinct species, which resembles H. proairrens. The leaves of the 

 secondary stems and branches are loosely spreading, deeply con- 

 cave from an erect base, roundish obtuse, the spores larger and 

 the operculum acuminate. As found in Hb. Jaeger (N. Y. Bot. 

 Gard.) it is 993 of Bryoth. Eur. 



3. Heterocladic squarrosulum compactum Mol. in Sched. 



Pfeffer, Bryogr. Stud. pi. 7/. 1869 



In dense, grayish green tufts. Primary stems stoloniform with 

 rudimentary leaves, not rarely defoliate ; secondary stems ascend- 



* Renauld & Cardot in Muse. Amer,, Sept. 49, 1892, extends the range to Wash- 

 ington. 



