PROTONEMA OF MOSSES. 



245' 



Another moss, a species of Bryum, on the other hand, which 

 I have had under observation for some considerable time, shows 

 very different protonemal features. The piece of ground on which 

 it grows is shady, but dries up rather quickly. Up to the present 

 it has" apparently never been damp long enough to allow of the 

 proper growth of the moss plants, although tiny plants can be- 

 seen sparsely scattered over the ground. The fruiting stage has 

 certainly never been reached m the last three years. The ground, 

 however, always becomes green after rain. The green is due to 

 an enormous number of small rod-like filaments, each one having 

 usually four cells. The number of cells is, however, variable, but 

 usually never more than ten, and then small branches are often 

 present. This branching stage is the beginning of a tufted con- 

 dition. One cell develops many branches, each of which has about 

 four cells. These pieces now become easily detached, thus causing 

 dissemination of the proton ema. Moss buds may arise from any 

 cells of these short filaments (Fig. 2). Gametophyte proliferations 



FIG. 2. 



are fairly common amongst mosses, notably in many species which 

 give rise to filamentous proliferations from the leaves, several 

 species which give rise to gemmae from the moss plants themselves, 

 the formation of bulbils, and the power the rhizoids possess of 

 changing into protonema. A portion of the ground has lately been 

 kept under more suitable conditions of moisture, and so far the 

 results appear to show that the rod-like filaments become more 

 protonema-like in character with the production of many more 

 buds. It would thus appear that the method here described is a 

 response to xerophytic conditions, by means of which the plant 

 extends its existence until more permanent conditions of growth 

 arise. 



