34 LICHENES OF THE NORTHERN STATES 



lia, ^- anthelina, Ach. — p. hispida, Fr. ; lacinias ascendant, hispid on 

 the margins, or tubulose-inflated. Fr. I. c. Borrera tenella, Ach. — y. 

 (tribracia), Fr. ; lacinise ascendant, squamulose, sparingly fibrillose, 

 pulverulent at the apices. Fr. I. c. Lecanora iriiracia, Ach. part. 



Trunks, dead wood, and rocks, very common; New England. New 

 York, Torrey. Pennsylvania, Muhl. Illinois, Russell! Northward 

 to Arctic America, Rich. 



32. P. ccBsia, Ach. Th. subcrustaceous-membranaceous, substellate, 

 gray (and cinerascent), besprinkled with gray soredia ; pale on the un- 

 der side ; laciniiE linear, somewhat convex, subpinnatifid, ciliate-fibril- 

 lose ; apoth. sessile, margin thin, somewhat infiexed, entire, disk at 

 length naked, black. Fr. Lichenogr. p. 83. — «. {stellata), Fr. ; laciniae 

 stellate-expanded, fibres shorter, soredia regular ; P. casia, Ach, ; and 

 the laciniae sometimes very narrow. Fr. I. c. P. duiia, Fl. — (3. {squa- 

 mulosa), Fr. ; lacinisB squamulose, short, obsoletely fibrillose. Fr. I. c. 

 Lecanora trihracia, Ach. part. 



Rocks, stones, and dead wood, fertile ; New England. New York, 

 Halsey. Pennsylvania, Muhl. 



33. P. ohscura, Fr. Th. submembranaceous, orbicular, not prui- 

 nose, greenish, becoming livid-fuscous when dry ; black and fibrillose 

 on the under side ; laciniaj sublinear, somewhat plane, incised-multifid 

 (often sorediiferous, or the margins pulverulent) ; apoth. sessile, very 

 entire, disk naked from the first, black-fuscous. Fr. Lichenogr. p. 84. 

 P. cycloselis, Ach.^§. ulothrix, Fr. ; laciniae linear, subciUate, apoth. 

 fibrillose below. Fr. I. c. P. ulothrix, Ach. 



Trunks, dead wood, &c., and passing into several degenerate states ; 

 New England. New York (a and /?), HaZsej/. Pennsylvania (^), iliuA?. 

 Ohio ((3), Mr. Lea ! Northward to Arctic America (a). Rich. — A very 

 distinct species detected recently by Mr. Oakes (P. Tuckermani, Oakes 

 ms.) may be referred to here. Resembling generally small greenish 

 forms of P. parietina, this differs in the foliose-lobate margins of the 

 apothecia, which are also fibrillose beneath, as in P. obscura,'(3. It is 

 common on trunks about Boston {Oakes, Tuckernian), and I have 

 found it on rocks at the White Mountains. It was sent from Ohio by 

 the late T. G. Lea, Esq. (Herb. Russell !), and I have North Carolina 

 specimens from Mr. Curtis. (What is P. fibrosa,-F\:, referred to in- 

 cidentally, Lich. pp. 75, 97 ?) 



