WOODLANDS 267 
phytes, apart from a few ferns (e.g., Polypodium vulgare), 
mosses, liverworts, and lichens, are mostly accidental. 
Lianes, or woody climbers, which form such a character- 
istic feature of tropical forests, are merely represented in 
our woods by the honeysuckle, ivy, and clematis. Many 
of our forest-trees, living in soil rich in humus, are partial 
saprophytes, their roots being clothed with a mycorhizal 
fungus instead of root-hairs (see p. 124). 
Natural and Artificial Woods. 
These islands were once far more extensively wooded 
than they are now, although it is still a well-wooded 
country. Most of the huge forests which once covered 
Fic. 112.—Tue Same Woop as In Fic. 111, shHowrne DIstRIBUTION OF 
Bracken. (Arrer WOODHEAD.) 
i ae ee | 
j|il]) Pteris aquilina (bracken). 
efrrde 
the land have been cut down for economic purposes, or 
cleared to make way for cultivation and pasture. Much 
of what remains has been seriously interfered with and 
modified by man, by periodic cutting and replanting, and 
in many places new woods. have been planted on arable 
land and pasture. Artificial woods are not always easy 
to distinguish from natural woods, especially when they 
are old-established, and felled portions have been re- 
planted with trees native to the soil and common to the 
district. Natural woods regenerate themselves by seed, 
and in them trees are seen in all stages of development ; 
