148 



Aquatic Organisms 



The true water mosses of the genus Fontinalis are 

 fine aquatic bryophytes. These are easily recognized, 

 being very dark in color and very slender. They grow 

 in spring brooks and in clear streams, and are often seen 

 in great dark masses trailing their wiry stems where the 

 current rushes between great boulders or leaps into 

 foam-flecked pools in mountain brooks. 



Another slender brook-inhabiting moss is Fissidens 

 julianum, which somewhat resembles Fontinalis, but 

 which is at once distinguished by the deeply channeled 



bases of its leaves, which 

 enfold the stem. The 

 leaves are two ranked and 

 alternate along the very 

 slender flexuous stem, and 

 appear to be set with edges 

 toward it. 



There are also a few 

 lesser water mosses allied 

 to the familiar trailing 

 hypnums, so common in 

 deep woods. They grow 

 on stones in the bed of 

 brooks. They cover the 

 face of the ledges over 

 which the water potirs in 

 floods and trickles in times of drouth, as with a fine 

 feathery carpet of verdure that adds much to the beauty 

 of the little waterfalls. They give shelter in such places 

 to an interesting population of amphibious animals, as 

 will be noted in chapter VI, following. The leaves of the 

 hypnums are rather short and broad, and in color they 

 are often very dark — often almost black.* 



Fig. 60. Water mosses. 



a, Fontinalis; b, Fissidens julianum, with a 

 single detached leaf, more enlarged; c, 

 Rhynchostegiunt rusciforme, with a single 

 detached leaf at the left. (After Grout.) 



*Grout has given a few hints for the recognition of these "Water-loving 

 hypnums" in his Mosses uith a Hand Lens, 2d edition, p. 128. New York, 

 1905- 



