196 LICHENS. 



fields furnished rne with good specimens of the Hole 

 lichens, so called from the depressed points in the warts 

 (Pertusaria). The common species (P. communis, Plate 

 XII I., fig. 11), is like a circular grey patch, with warts 

 crowded against one another. 



Of the nearly allied family, the perforated lichens 

 (Thelotrema), I could find no specimen. 



There were no scattered-spot lichens to be found (Spiloma), 

 though I remembered often to have seen the minute con- 

 fluent receptacles of the wall species upon mortar. This 

 family also contains many members, but they are too 

 minute, and resemble each other too closely to draw 

 much general interest. 



In a wood, composed partly of firs, near the toll-gate, 

 I found a pretty circular lichen ; the margin was zoned 

 and the inner part was sprinkled with white powder, 

 while several shields were planted towards the centre. 

 These were the receptacles, and boasted a torn border. This 

 was the circular pustula lichen, the family name being 

 the result of the swollen receptacles (Variolaria globuli- 

 fera.) A tree near the edge of the wood bore large 

 patches of the "inelegant pustula lichen" (V. agelaea) ; 

 its grey crust with patches of white powder was so unas- 

 suming as to deserve the term inelegant. But these lichens, 

 formerly erected into a separate family, Variolaria, are 

 now ascertained to be only gonidial states of other 

 lichens. 



I now hastened my return, as the dinner hour could 

 not be far distant ; in this, however, I was deceived, for I 

 had passed the off-shoot of the original village which is 

 now called Highgate, when the unerring clock of the fine 



