FINK—THE LICHENS OF MINNESOTA. 53 
The genus is plainly most closely related to Graphis, though its relation to Arthonia, 
Melaspilea, and Lecanactis is not remote. 
Four species and subspecies have been found in Minnesota. 
Type species Opegrapha vulgaris Wumb. loc. cit. This is a synonym for Graphis 
scripla, and the name Opegrapha becomes invalid and will need to be changed when 
all lichen genera have been typified. 
KEY TO THE SPECIES. 
Parasitic on other lichens. ..............-.-------------+---- 2. O. quaternella. 
Not parasitic on other lichens, 
Apothecia lanceolate .............------- +--+ 2222 eee eee ee- 1. O. varia. 
Apothecia not lanceolate. 
Apothecia oblong-ellipsoid .............-------------- Ib. O. varia pulicaris, 
Apothecia oblong or suborbicular........----.------- la. O. varia notha. 
1. Opegrapha varia Pers. Ann. Bot. Usteri 7:30, 1794. Puate 1, B. 
Epiphleodal portion of the thallus a thin whitish film forming a continuous or 
more or less scattered layer upon the substratum, or disappearing; apothecia lanceo- 
late, small, 0.2 to 0.4 mm. wide and 0.4 to 1.5 mm. long, adnate or more or less 
immersed in the substratum, the disk black and usually more or less furrowed, the 
exciple black and prominent, persistent and heavy; hypothecium blackish brown; 
hymenium pale below and darker above; paraphyses rarely branched, sometimes 
more or less coherent, commonly enlarged and darkened toward the apex; asci cla- 
vate or eylindrico-clavate; spores hyaline or brownish, 4 to 6-celled, fusiform, 15 to 
24 « long and 5 to 8 # wide. 
Generally distributed in the State. On trees. 
Also distributed throughout North America. Known also in Europe and Africa, 
EXPLANATION OF PLATE 1. See page 48. 
la. Opegrapha varia notha (Ach.) Nyl. Not. Siillsk. Faun, Flor. Penn. 5: 253. 1861. 
Lichen nothus Ach, Lich. Suec. 19. 1798. 
This form is distinguished by the oblong or suborbicular apothecia. 
Collected at Rose Lake in the northeastern portion of the State. On cedars. 
Does not appear in any American lichen lists known to me, though it is credited 
to our continent by Europeans. Occurs in Europe and Africa. 
1b. Opegrapha varia pulicaris (Ach.) Nyl. Not. Sillsk. Faun. Flor. Penn. 5: 253. 
1861. 
Opegrapha vulvella pulicaris Ach. Lich. Univ. 251. 1810. 
Distinguished by the oblong-ellipsoid apothecia with commonly connivent exciple. 
The apothecia are smaller in ours. Determined by A. Zahlbruckner. 
Collected at Granite Falls. On trees. There may well be some doubt as to the 
worth of these subspecies, but such as they are, they doubtless are to be looked for 
elsewhere in Minnesota. 
Elsewhere in North America in New England, Ohio, Iowa, and Nebraska. In all 
the grand divisions except South America. 
2. Opegrapha quaternella Nyl. Flora 68: 449. 1885. 
Parasitic and no thallus discernible except that of the host; apothecia irregular 
in form and usually densely clustered, minute, 0.2 to 0.3 mm. in diameter, irregu- 
larly oblong where sufficiently distinct to show form, the exciple black and irregular; 
hypothecium dark brown; hymenium more or less brown or brownish; paraphyses 
distinct and rarely branched, commonly enlarged and darker toward the apex; asci 
clavate; spores 4 in each ascus, hyaline, oblong or oblong-ellipsoid, 16 to 22 /¢ long 
and 5 to 7 4 wide. 
