288 PLANT LIFE. 



the soil it is overflowed and killed out by grasses and 

 Dicotyledonous weeds. 



Thus, we see that these former giants of geological 

 vegetation, now form either a series of Celtic fringes on 

 the hills, and upon specially barren ground ; or, in many 

 cases, that they have been overflowed by the more highly 

 developed plants, and now cling tenaciously to menial 

 positions which require only a poor sort of structure ; 

 but which are none the less of advantage to the Forests 

 or Marshes in which we find them. The Peatmoss stands 

 out as a sort of Chinese type which cumbers the 

 ground, and still defies, not merely the highest organised 

 of vegetables, but even man himself. 



The subsequent history of the Pines, Oaks, and 

 Mixed Woods, and of the modern British Flora, will 

 be found in Chapter XV. 



It is therefore clear that Ferns, Clubmosses, and 

 Horsetails, though at present the}^ are probably less 

 useful to man than any other kind of vegetation, have 

 had a very important share in the preparation of soil fit 

 for higher and more specialised plants. 



