Mr. Turner's Descriptions of Eight Nezv British Lichens. 1 13 



ed among our most beautiful British species. I received it 

 many years ago from Spain upon the young shoots of smooth- 

 barked trees, but it appears to have been found in England only 

 upon the bare surface of flints, over which it spreads in patches 

 of most irregular form and size, bearing in its more early stage, 

 before the shields are yet visible, the strongest resemblance to 

 Verrucaria umbrina. It needs scarcely to be remarked, that the 

 even substance upon which it grows is the cause of its not un- 

 frequently occurring with an elegant border, composed of the 

 most minute glossy parallel fibres, the same being common to 

 many other crustaceous Lichens under similar circumstances. I 

 apprehend that the cause of Lecidea airo-Jiavas having so long 

 escaped notice, must depend either upon its being a very un- 

 common species, or upon its being overlooked as a variety of 

 Lecidea cinereo-fusca*, with which it frequently grows intermix- 

 ed ; but from which it may at all times and at first sight be 

 distinguished, not only by the colour and nature of the crust, but 

 by the shields, which are in the one remarkably vivid, and in the 

 other no less remarkably dull. I am not aware that there is any 

 other Lecidea to which the present approaches so nearly as to 

 make it necessary particularly to point out the essential charac- 

 ters that discriminate them. 



Parmelia velata. 

 Parmclia crusta determinate membranaceo-verrucosa rugulosaV 

 albicante; scutellis exiguis congestis, disco piano ilavicante 

 membrana albicante obtecto. 



Tab. XII. Fig. 1. 

 On ash trees in Sussex ; rare. Mr, Borrer, 



* Lichen ferrvgineus of British authors. 



Alga 



