Sub-genus Calliergon 



Leaves at the base of the pedicel (perich&tial leaves). Numerous, 

 whitish, erect ; and close, the cells loose. 



Habit of flowering. Male and female flowers on separate 

 plants (dioicous}. 



Veil (calyptra). Thin and split up one side. 



Spore-case. Large, oblong, swollen, and arched, when young; 

 thin and distinctly ribbed, when dry. 



Pedicel. Long and slender. 



Lid (operculum). Conical, with a short abrupt point. 



Teeth (peristome). Yellow with small blade-like projections 

 on the inside ; segments of the inner membrane slightly cleft ; 

 cilia 2 to 3, nearly as long as the segments. 



Annulus. With three rows of cells, rolling back as the 

 lid falls. 



Spores. Mature in fall. 



Distribution. North America. 



THE EXQUISITE FEATHER-MOSS 

 HYPNUM, Sub-genus CALLIERGON 



The species of the Sub-genus Calliergon are large, erect, or 

 prostrate plants growing in wide mats on the ground, or on 

 rocks; the branches are simple or compound and have but a few 

 rooting filaments. 



The sub-generic name is the Greek word /caX\.iepyov, beauti- 

 fully made. 



Spore-case 

 Stem-leaves. Spore-cases with lids. without lid. 



H. Schreberi. 



The leaves are heart-shaped, oval or oval-oblong, deeply con- 

 cave, spreading or overlapping, rarely turned to one side; the 

 apex is obtuse, the vein variable, and the cells linear above and 

 four-sided at the basal angles. 



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