HEATH TRIBE. 



393 



able for their social nature ; extensive tracts of conn- 

 try being often fonnd entirely covered with, a few species, 

 so as to give name to the kinds of places -on which they 

 grow. They are most abundant in the neighbourhood 

 of the Cape of Good Hope ; hence they are often called 



ERfCA TETRALIX, E. CILlAaiS, E. VAGANS, and E. CIN^REA. 



by gardeners', " Cape plants." They are common also 

 in Europe, in North and South America, both within 

 and without the tropics, and in the mountainous parts 

 of Asia. The extensive genus Erica i(Heath) contains 

 no plant possessing useful properties. Calluna vulgdris 

 (Ling, or Heather) is astringent, and is sometimes used 



