212 PERTUSARIA. 



sessile, a little elevated, thick ; the lecanorine disk flattish, 

 rugulose, soon dilated so as to depress and exclude the turgid 

 thalline margin; from brownish-liver-coloured becoming livid, 



and blackening. Spores solitary, 1 ^'^ rnic. Lecanora, Ach. 



L. U. p. 392 ; Syn. p. 156. Pertusaria, NyL Scand. p. 178. 



On the earth, growing over mosses, etc., in alpine districts. 

 Greenland (Vahl), Th. Fries I c. 1861. Islands of Behring's 

 Straits, Wright. Shores of River St. Mary, Lake Superior, 

 Richardson (Leighton L c.). 



2. P. velata (Turn.) Nyl. j thallus cartilagineous, smooth, 

 Becoming plicate-rugose and chinky ; glaucescent, and white ; 

 with a zonate and more or less brighter-coloured circumference ; 

 apothecia small to almost middling-sized, adnate, lecauoroid; 

 disk flattish, pale-yellowish- to reddish-flesh-coloured ; densely 

 white -powdery; the thick, entire thalliue margin becoming 

 finally indistinguishable in the now difform, and often 2-3-thala- 

 mous fruit. Spores solitary for the most part ; exceeding ^^ 



mic.- Turn, in Act. Linn. Lond. 9, p. 143, t. 12, /. 1. Pertu- 



saria,Mudd. Man. Brit. Lich. p. 274. 



Trees, and also on rocks, throughout the Atlantic regions 

 from New England to Virginia, Tuckerman Gen. 1872. Canada, 

 Macoun. North Carolina, Curtis. Alabama, Peters. Ohio, 

 Lea. Illinois, Hall Texas, Hall. 



3. P. panyrga (Ach.) Th. Fr. ; thallus incrusting, thin, 

 wrinkled; white; apothecia small to almost middling-sized, 

 lecanoroid but often 2-3-thalamous; the depressed disk black, 

 white-powdery ; the thalline margin irregular. Spores " soli- 

 tary ; ^^ mic." Th. Fr. Scand. p. 308. P. velata * multi- 



puncta v. leucotera, Nyl. Scand. p. 1 80. 



On the earth, running over mosses, etc., in alpine districts. 

 Greenland (Vahl), Th. Fries I c. 1861. 



4. P. multipuncta (Turn.) NyL; thallus sub-cartilagi neons, 

 oftener thin and chinky but becoming rugose-verrucose ; glau- 

 cescent and pale-ash-coloured ; zonate more or less at the cir- 

 cumference, as in n. 2, but less distinctly; apothecia small to 

 almost middling-sized, lecanoroid, adnate, at length elevated; 

 mono- or now 2-4-thalamous ; with flat, blackening disk ; but 

 becoming depressed and very irregular ; and, excluding the 

 soon gaping thalline margin, passing into diffortn, powdery 



