a 
IV. Description of a new Species of Lichen. By Dawson T ihr er, 
Esq. F. R.S. A.S. and L.S. 
Read A pril 17, 1804. 
' LICHEN PHÆOCEPHALUS. 
Licuen crustå e granuloså sub-foliaceá fuscescente; bacillis ni- 
` gris; tuberculis rufo-fuscis, margine luteo-albicante,, ; 
v es 
E [ w Tan. VI. Fig. 1... F3 
Innascitur horreorum- assibus apud Bruisyard in $ 
Lakenham in Norfolcià. —— i 
juffolcià, et 
Crusta latè effusa, crassiuscula, e granulis sub-gelatinosis, satis 
inagnis, incisis, folia'simi lantibus, madore diluté viridi-fuscis, 
- siccitate nigricantibus, dens congestis constans ; bacilla nigra, 
lineam fere alta, crusta , aut ne vix superantia, apice in 
tuberculum sub-rotundum, pulvere rufo-fusco repletum, et 
margine tenuissimo, albicante, vel luteolo cinctum, tumes- 
centia. Tuberculorum pulveris marginisque color in siccis 
madidisque idem. 
I should not trouble tl eL m nean Society with a description 
and figure of this single lic len, were it not for its close affinity 
to L. chrysocephalus, which I described in a former paper*. I re- 
garded that species as an interesting addition to. our Lichenogra- 
phia; but the present, whici 1 I have since been fortunate enough 
to find in two places, is still 1 nore interesting, on account of the 
singular nature of its crust. - In this respect it essentially differs 
* Linn. Trans, + vol. vii. p.88, Eu m - 
d pl ee from 
