88 MOSSES AND LIVERWORTS 



small round head, as in my drawing. If this 

 round head is still further magnified (fig. 10), 

 it will be seen that it is made up of a great 

 number of minute, egg-shaped bodies, packed 

 very closely together. These again are gemma, 

 and a few of them, on a considerably large scale, 

 are given in fig. 11. Plate VI. fig. 14 shows a 

 leaf of the R/oughish-leaved Screw-moss (Tortula 

 papillosa), a name given to the plant by reason 

 of the fact that the surface of the leaf is 

 roughened, or papillose, a condition which is by 

 no means confined to the leaves of this particular 

 species. This moss, which grows in dark, olive- 

 green tufts on the trunks of trees, is, I believe, 

 never found in fruit in Britain, and new indi- 

 viduals arise by means of bud-like growths, which 

 are developed on the upper faces of the leaves, 

 clustering round the midrib, or nerve, as shown 

 in the drawing ; fig. 17 represents a few of these 

 bodies more highly magnified. In the Frizzled 

 Bristle-moss (TTlota phyllantha) referred to not 

 long since, the buds are formed in a cluster at 

 the very tip of the leaf, and have all the ap- 

 pearance, at first sight, of some brown fungoid 

 growth. 



Now, in all such cases, if one of these tiny 

 bodies falls to the ground and begins to grow, 

 it gives rise to that curious thread-like growth 

 (protonema) which, as we saw at the outset of 

 our story, is usually the first stage of the 



