PROFIT AND LOSS 139 
annuals which have followed the spread of farming 
operations, or which are directly—though uninten- 
tionally—introduced by man as impurities in the seed 
which he sows. 
Let us look a little more closely into the question 
of profit and loss in our flora resulting from agri- 
culture. In the first place, whether the ground is 
tilled or grazed, the woodland which primitively 
occupied so much of it disappears. The plough and 
the scythe are fatal to all seedling trees. Little less 
fatal is the browsing of cattle and sheep, and even in 
rough pasture only thorny plants like Whitethorn 
and Gorse may be found battling successfully for a 
lodgment. Where woodland is used for pasturage, 
the delicate shade plants—Anemones, Wild Hyacinths, 
Primroses—soon die out. No young trees appear on 
the grazed surface, though hundreds of thousands of 
seeds may be shed annually over the ground. In the’ 
course of time the present trees will die, and only 
grass remain. How different is it where cattle are 
excluded and the scythe unused! Among the grass 
young trees spring up everywhere, and in the woods 
a dense undergrowth of saplings sheltering a varied 
shade flora makes its appearance; regeneration of the 
natural woodland proceeds apace. 
Natural grasslands, if undisturbed, possess a flora 
which has been built up during a long period of time, 
and which, like all purely natural plant associations, 
represents a delicate balance between its many con- 
stituents, which often include rare and shy species. If 
such land be once broken up, its flora will probably 
never again resume its former composition even if 
allowed to regenerate during a long series of years, 
