Mr, Turner's Descriptions of Eight New British Lichens. 141 



Alga Crustacea, muralis, effusa. 



Crusta in puJvinulum inflata, pollicem circiter diametro, e gle- 

 bulis lota constans : glebulae approximata?, vix conjuncta?, in- 

 terdum laxe imbricatae, papavcris semine majores, compressa?, 

 orbiculares, vel margine irregulariter lobatae ; recentes aeque. ac 

 desiccata alba^, aut einereae, interdum viridescentes. 



Patellula per to tarn crustam absque ordine sparsae, frequentes, 

 nee raro coacervatae, nigrae, ortu et siccitate concavae, margine 

 concolore, crasso, elevato, adultae hemisphaericae et marginis 

 expertes, orbiculares vel per mutuam pressionem angulosas. 



Substantia tartarea, in sicca fragilis. 



The most striking peculiarity of this Lichen must certainly be 

 considered the delicious and highly aromatic fragrance which 

 both the crust and shields, but especially the former, give out 

 when rubbed between the fingers in a recent state, and which, 

 though in a less degree, the plant often retains for some years. 

 In this circumstance I am not aware that any British Lichen re- 

 sembles it, excepting only Lecidea caruleo-nigricans, in which a 

 similar smell may sometimes, but by no means always, be per- 

 ceived. Lecidea aromatica belongs to so intricate and embarrass- 

 ing a subdivision of the genus, that, in spite of the peculiarity 

 just mentioned, which I have always found constant, I should 

 scarcely have ventured to propose it as a new species, had I not 

 in support of my own opinion the sanction of Dr. Acharius, 

 Dr. Swartz, and Mr. Borrer, the two former of whom consider 

 it distinct from any with which they are acquainted, and the 

 latter has been in the habit of observing it for many years, du- 

 ring which he has never found it liable to variation. Its closest 

 natural affinities are with Lecidea atro-alba and L, caruleo-nigri- 

 cans, between which it stands almost intermediate : of these the 



first 



