in. INTRODUCED SPECIES. 79 



America. — We may derive an useful liint from the facts 

 concerning these vai'ious species. They now occur in 

 England quite as well established among the natural ve- 

 getation, as are those of the more numerous group treated 

 under the designation of denizens in this work. Those 

 botanists who regard the denizens as being for the most 

 part true natives of Britain, do so on the ground of their 

 present seeming wildness or spontaneity in certain spots. 

 On the same rule, if their origin had been equally unre- 

 corded, the American species above named would equally 

 have been declared aboriginal natives of Britain, — and 

 yet of course wrongly so declared. How many of the 

 denizens are in this condition ? How many even of the 

 reputed natives, through the indications of their foreign 

 origin having become obliterated ? 



4. Fruit trees. — It might well be supposed that some of 

 the trees and shrubs, which have been long and largely 

 cultivated for their fruit, would gradually have become 

 established in England, if not aboriginal natives. And 

 further, there seems no improbability in a supposition, 

 that the descendants of such garden fruits would deterio- 

 rate in becoming wild here. Some botanists regard the 

 Pear, Apple, Plum, Cherry, Currant, and Gooseberry, aU 

 alike as aboriginal natives of Britain. This appears 

 doubtful in respect to some of them ; sufficiently probable 

 or certain in regard to others. Pyrus Mains occurs fre- 

 quently in hedgerows and coppices, in a seemingly wild 

 state ; though in such situations it is at any rate liable to 

 some degree of distrust. But trees of great age are found 

 occasionally on hill sides, and also in the scanty remains 

 of truly natural forests. These latter localities go far to 

 warrant our recognition of the Crab-tree or Wilding- 

 apple as a genuine native of England. On the contrary, 

 Pjfrus communis is far less frequent in the half-wild 



