142 PLANTS AND MAN 
drainage is carried; and so on. The indictment is an 
overwhelming one, and, as said in the first chapter, the 
flora is now everywhere so altered that we can gain 
some idea of its original aspect only by a study of 
isolated fragments and much-adulterated samples. 
But if the debit side of the account, as presented by 
the lover of nature, is heavy, it must not be forgotten 
that there are many items to man’s credit. Though 
our country’s vegetation has lost in scientific interest, 
it has gained vastly in both economic and esthetic 
value by the introduction of useful and ornamental 
plants from all the Temperate regions of the world; 
and besides, a large number of species have followed 
in man’s footsteps, and, taking advantage of the dis- 
turbance of the native flora caused by his operations, 
endeavour with more or less success to establish a 
footing in the country. Before we trespass on the 
domains of arboriculture, horticulture, or agriculture, 
under which heads the cultivation of useful or orna- 
mental plants divides itself, some consideration is 
required of those plants which, quasi-wild, are usually 
included in accounts of the vegetation under the head 
of aliens, denizens, colonists, and so forth. These 
constitute a quite considerable proportion of the total 
number of species found in any area which has felt 
the influence of man. For instance, in the county of 
Dublin, which, owing to its diversified surface—sea- 
cliff, sands, moorland, woodland, and cultivation—and 
its favourable climate—the warmest and driest in the 
country—possesses the largest flora of any similar 
area (354 square miles) in Ireland, the list of about 
760 “wild” plants includes some 170, or over one- 
fifth of the whole, whose presence is attributable, 
