FONTINALACEAE 117 



Seta short; capsule immersed in the perichaetial leaves or shortly 

 exserted, without neck or stomata; annulus lacking; peristome 

 double, the outer composed of 16 teeth, the inner of 16 linear 

 divisions more or less completely united by cross strands at regular 

 intervals, forming a regidar net or trellis through the meshes of 

 which the spores gradually escape. 



Although mosses belonging to several other families are 

 aquatic, the mosses of this family are most emphatically en- 

 titled to the name of Water Mosses, as the members of the fam- 

 ily are either submerged all the time or attached to objects 

 that are submerged at high water. 



Key to the Genera 



Costa lacking, leaves mostly symmetric Fontinalis 



Costa present, leaves mostly falcate-secund Dichelyma 



DICHELYMA Myr. 



Plants growing near the edge or surface of the water, generally 

 submerged at high water, shorter than Fontinalis with the ap- 

 pearance of Drepanocladus; leaves three-ranked, costate, nar- 

 rowly lanceolate, secund to falcate-secund; leaf cells narrow, 

 linear; basal shorter, brownish, not forming auricles. Dioicous; 

 perichaetium very long, cylindric, the leaves convolute, very 

 long, spirally twisted, ecostate; seta of moderate length en- 

 closed by the perichaetial leaves, sometimes longer and some- 

 times shorter than the perichaetium; peristome much as in 

 Fontinalis, but the teeth shorter than the inner peristome. 



D. capillaceum B. & S. Frequent on sticks and stones in 

 water. Ridgewood (25473) and Gowanus (25474), Northport, 

 Orient, Forest Park (25475)!!, L. Id.; Red Lane and Court 

 House, S. Id.; "Common," Muse. App. 252. 



FONTINALIS Dill. 



Stems usually denuded of leaves below, long slender and floating, 

 freely branched, usually blackish green, except the latest growth; 

 leaves ecostate, sometimes nearly flat, but usually strongly con- 

 cave to nearly tubular. (The young undeveloped leaves at the 

 ends of the shoots are always convolute.) Median leaf cells 



