140 THE SELAGINELLA RUPESTRIS GROUP. 



others of its kin, and so small as to be easily overlooked 

 unless one is on a special hunt for it. One who has 

 once seen it, however, will seldom overlook it again, for 

 the whole plant has a characteristic grey-green colour not 

 common to mosses, that is sure to catch the eye and 

 make recognition at some distance possible. 



The main stems of this species are from one to five 

 inches long and nearly prostrate. From these issue 

 great numbers of secondary branches, several times 

 forked, but all so short that the topmost branch does 

 not reach a height of three inches. The plants grow in 

 communities, with branches so intertwined that the 

 individuals are difficult to distinguish, the whole form- 

 ing a dense little mat that often covers an area of several 

 square feet. 



The leaves are arranged in about eight ranks, and so 

 close together upon the stems and branches as to 

 completely cover them. At the tips of the branches 

 they are more or less spreading, but elsewhere they are 

 rather closely appressed. They are frequently described 

 as less than a sixteenth of an inch long, but in vigorous 

 specimens they may reach more than twice this length, 

 exclusive of the awn-like tip. They are narrow, with a 

 deep groove on the back, and taper from the base to the 

 rounded apex. Each leaf bears a slender white bristle 

 at the tip, which is one third to one half the length of the 

 leaf. It is these white bristles among the green that 

 give the peculiar greyish colour to the plant. The 

 leaves also bear numerous cilia on the margins, and the 

 bristles also have very short ones. 



The fertile spikes are similar to ordinary branches in 

 appearance, the most noticeable differences being that 

 they are erect and distinctly four-sided. Thesporophylls 



