INTRODUCTION. 19 



server, is the PRIVILEGED LOCALITIES certain rare 

 species assume, most of which must be esteemed 

 undoubtedly indigenous in such restricted bounds ; 

 and, puzzling as they are to account for, on mere 

 geographical principles, it would seem as if nature 

 had herself planted them, but circumstances had in 

 some way precluded their extension. I subjoin the 

 more remarkable of these stations, as not coming 

 within an every-day look out, and it is moreover con- 

 venient to see them at a single glance, 

 Arabis liispida, on the rocks of Clogwyn du yr Arddu, 



Snowdon. 



Arabis stricta, on St. Vincent's rocks, on the side 

 of the Avon, below Bristol. Other rare plants oc- 

 cupy this picturesque ledge of " Bristol Limestone," 

 which is situated on the Gloucestershire side of 

 the river. The Leigh woods, and carboniferous 

 limestone, abounding with Pyrus Aria, Grammitis 

 ceteracli, &c., are on the southern or Somersetshire 

 bank of the river. 



Draba aizoides, on the walls of Pennard Castle, Gla- 

 morganshire, and it is reported by Mr. DILLWYN, 

 also on inaccessible rocks, near the Worm's Head. 

 Found nowhere else in Britain. 

 TJilaspi alpestre, chiefly on the rocks about Matlock, 



Derbyshire. 



Thlaspi perfoliatum, on the Oolite of the Cottes- 

 wold Hills, Gloucestershire, near Naunton Seven 

 Springs.* 

 Heliantliemim poUfoliurn,, on rocks at Babbicombe, 



* See Professor BUCKMAN'S Flora of Cheltenham, an interesting record 

 of the plants of the Cotteswolds, among which is the rare and beautiful 

 Melittis grandiflora growing in a wood called Puckhara Scrubbs. 



c2 



