34 PLANT-LIFE ON LAND [CH. 



the branching may be further repeated, so that the 

 whole leaf takes a highly divided form. The ultimate 

 ramifications widen out into green expansions which 

 collectively make up the lamina or region of the leaf 

 effective for self-nourishment. So well is this function 

 carried out that a large overplus of the material 

 gained is stored in the fleshy tissues of the under- 

 ground stock, and carried over as a physiological 

 balance to the ensuing season. 



It is no wonder that a plant having the advantage 

 of a well-developed stock for storage, deeply buried 

 in the ground and so protected against risks from 

 climate as well as from animal attack, should succeed. 

 But in many districts, and especially in the North of 

 Scotland, its success is embarrassing to the farmer who 

 wishes to graze sheep, or to the forester who has to 

 plant out a hillside. To them the question is how to 

 extirpate it cheaply and effectively. The method in 

 common practice is physiologically sound. It is to mow 

 down the leaves about the end of June, that is so soon 

 as the leafage is approaching full development. The 

 process is to be repeated a second, or if necessary 

 a third year. Some may think that this succeeds 

 because the propagative spores, which as we shall see 

 are borne upon the leaves, are checked in their 

 development, and so their germination is prevented. 

 But it will be pointed out that the growth of new 

 plants through the germination of spores is uncommon 



