136 SEA MOSSES. 



sexual fruit, and usually appears in minute clusters 

 upon the branches of fertile fronds, or else encased 

 in little egg-shaped baskets, or other receptacles. It 

 is also not unfrequently found embedded in the sub- 

 stance of membraneous fronds, or held in wart-like 

 protuberances which arise from their surface. 



The other or asexual spores are produced, ap- 

 parently, by a change in some of the vegetable cells 

 of the plant. They always appear in groups of four, 

 hence their name, " Tetraspores" or " Tetragonidia" 

 The original, or " Mother cell," seems to part its 

 contents invariably into four secondary cells, and each 

 of these is capable of reproducing the plant. They 

 are found in various situations, but, except in some of 

 the lower plants of the grouu>, always occur embedded 

 in the substance of the frond. It is a rule, which jo 

 far as I know, has no exception, that the two kinds 

 of fruit never appear upon the same individual plant. 



The Red Mosses will no doubt make up the prin- 

 cipal part of all your collections. Certainly they are, 

 as a general thing, more interesting and more beautiful, 

 and appear in much greater variety of form, than those 

 of the other classes. Some of them are marvelously 

 fine and delicate, and make the most exquisite and 

 fairy-like pictures when spread out upon paper. The 

 wonder is, how such fragile things can find the means 



