THE STATE PROTECTION OF WILD PLANTS 631 



The ridge and furrow of the midlands testify to the former 

 extent of cornlands and illustrate the purely local character of a 

 method of drainage which caused little more than local disturb- 

 ance of conditions without removing them. They allowed for 

 an alternation of xerophilous and hygrophilous plants without 

 driving out either class. 



Where this primitive type of drainage alone persists, what 

 I have ventured to call " vestigial floras " or remnants or indica- 

 tions of the real natural plant-formations will be found surrounded 

 by a modern mesophytic type of vegetation. The insignificance 

 of the vestigial floras affords, in the field, an optical demonstra- 

 tion of the immensity of the changes wrought by this one factor 

 alone, the removal of water by drainage. Where, moreover, 

 land is drained by modern processes, by carrying the water by 

 drains to ditches, thence to streams, lastly to rivers and the sea 

 or lakes, the change is complete. There are not even traces of a 

 vestigial flora — there is in fact no aboriginal flora. Its place has 

 been taken by another type of flora. 



If the grass-pastures alluded to are converted into cornfields, 

 there will be fresh changes. And a fresh race of alien plants 

 will impress itself upon the remnants of mesophytic vegetation. 

 This like the preceding phase will be artificial and from the 

 point of view of the continuance of natural plant-formations is 

 an instance of wholesale extermination on a very large scale. 

 And from the scientific point of view, extermination must be 

 examined in the light of the original not the derived or secondary 

 plant-formations. 



Another important cause of disturbance and extinction is the 

 extension of building operations. The later extensions and 

 modifications of the City of London have brought about extra- 

 ordinary changes, as may be proved by comparing Curtis's 

 Flora Londinensis with the present flora. The increased 

 attention given to sanitary conditions leads to the alteration or 

 pulling down of old dwellings in old towns ; in this connexion 

 their very antiquity is the point of importance. Cryptogams, 

 particularly Lichens and Mosses, are especially addicted to 

 such habitats and are destroyed by the pulling down of old 

 buildings, whilst the erection of new buildings on fresh ground 

 involves the destruction of other habitats, since the sites 

 chosen are invariably the areas occupied by plants not found 

 elsewhere. This is especially the case where towns, as is often 



