Urccolaria.} \ LICHENES. 171 



In this instance, only, so far as regards the present genus, do I differ 

 from the learned authors of the Lic/wnographia Britannica, by consider- 

 ing this plant rather as a Variolaria than a Parmelia (Lecanora, Ach.). 

 Its crust and general habit, as Sir James E. Smith observes, are those 

 of Variolaria \iultipunctata, where the powder of the shields is very 

 deficient, and where the disk (lamina proligera) is very evident. Here 

 the disk is still more copious, the powder is entirely absent, and its place 

 is supplied, if I may use the term, by a white membrane, stretched 

 across the whole apqthecium. If, however, it be placed among the 

 LecanorcE it must rank with L. Parella. 



12. V. argena, Turn, and Borr. (silvery Variolaria); crust sub- 

 orbicular between filmy and tartareous very thin rugulose grey 

 covered here and there in patches with white powder surrounded 

 by a white fibrous border, apothecia in scattered clusters orbi- 

 cular flattish with an inflexed border, powder white not abun- 

 dant. Turn, and Borr. Licit. Br. p. 75. — Lichen argcenus, and 

 L. agelceus, (according to Ach.) Ach. Prodr. p. 8. E. Bot. 

 t. 1923, (bad). — Lecidea argccna, Ach. Meth. (not Syn.)—The- 

 lotrcma variolar hides, (3. Ach — Lichen farinosus, Hoffm. — 

 Lecanora verrucosa, Ach. Lich. Univ. p. 354.— y. Ach. Lich. 

 linr.p. 355. 



On the bark of Lime and other trees, not uncommon. 



13. V. agelcva, Turn, and Borr. (inelegant Variolaria); crust 

 elliptical almost filmy whitish surrounded by an obsolete border 

 of the same colour, apothecia very numerous depressed shape- 

 less crowded and becoming confluent so as to appear com- 

 pound with an inflexed border, powder white, the disk at length 

 bare blackish. Turn, and Borr. Lich. Br. p. IS.— Lich, „ 

 agelceus, Ach. Meth.—E. Bot.t. 1720— Thelotrema variolarioidcs. 

 [3. agelcea, Ach. Syn. p. 117 — Urccolaria agelcBO, Ach. Meth*— 

 Lecanora verrucosa, $. Ach. Lich. I inc. p. 355. 



It will be seen by the synonyms of this and the preceding Lichen 

 what different opinions have been held, even by Acharius himself, rc- 

 Bpecting their generic and .specific identity. At length, in his Sunnpsis, 

 he has referred both of them to one and the same variety of Thelotrema 

 variolisriokk , V. ageUea is ranked by Messrs. Turner and BoTfei 

 among the Variolarics, on account of the presence of the powder in the 

 young and rigorous Btate of the plant ; mil thej still call it an "obscure 

 Lichen." T1h\ observe that it differs from V. argena aiul V. multi- 

 punctata, in the thinner and more even thallus, and in the shape and 



structure, as wdl as in the greater number, of its apothecia. — Some <>t 

 the figures '" /; - 1! "'- B PP car to mc to hears great resemblance to 

 Pertusaria communis. 



e, Apothecia bordered, discoid, sessile (jxtfeltul 



Pam. VI I. Leg inorv i . 



Il\ I'k< BOL \ki \. Acht licrolaria. 



ThaUus crustaceous, spreading, adnate, uniform. Apothecia 

 (patelluUe) orbicular, the dish concave, coloured, immersed in 

 the csust tin- bordi i formed of the crust ami of the Mune .-.dour. 



