LICHENS 205 



top, and let it stand three or four days. If any colour is 

 likely to be obtained, it will then be evident in the 

 liquid." 



When climbing to the topmost group, we overlook 

 the beautiful valley of the Swale and the crowd of gray 

 hills stretching beyond it on every side till their outline 

 becomes so faint as to be hardly distinguishable from the 

 horizon, and still behold the Crab's-eye and Cudbear 

 peopling the commanding rocks, we think of Darwin's 

 description of the plant : — 



" Retiring lichen climbs the topmost stone, 

 And drinks the aerial solitude alone." 



One February, when exploring the banks of the Looe 

 river, near Looe in Cornwall, we came to an old wall 

 sometimes formed of sandstone rock, sometimes built into 

 it. Here we first found members of the Psorse, or Scurf 

 lichen family. One composed of light green scales lined 

 with white, and bearing orange shield-like receptacles, 

 was the Brown Scurf lichen (Psoras globulosa, Plate XIV., 



fiy- 13). 



Near it was a black and gray-speckled lichen, of the 

 same form, the so-called Black and Blue Scurf lichen 

 (P. ceruleo nigricans, Plate XIV., Jig. 14.) Some small 

 orange specks on the ground showed similar structure 

 under the magnifier, and thus declared itself to be the 

 Black and Eed Scurf lichen (P atro-rufa). There is the 

 raspberry-fruited and the staircase species ; but we have 

 not found either. 



The next family is that of the Squamariae or Scale 

 lichens. The Shield lichens are the last of the crusted 



