FINK—THE LICHENS OF MINNESOTA. 189 
pressed-subglobose (not disk-shaped) and variously irregular, apothecia 2 to several 
in each verruca, and the verruce closed except at the sunken, commonly black but 
usually inconspicuous pores of the apothecia; hypothecium pale; hymenium pale 
below and sometimes more or less brownish above; paraphyses slender and usually 
Fig. 15.—Pertusaria communis. a, Thallus with the apothecia-containing verruce and the ostioles; b, a 
section of a verruca, showing two of the immersed apothecia. a, Enlarged 3 diameters; b, 30 diameters. 
From Reinke. 
more or less branched; asci cylindrical or cylindrico-clavate; spores 100 to 180 4 long 
and 40 to 70 ” wide, 1, 2 (or rarely 4 ?) in each ascus. 
Generally distributed throughout the State. On trees and rarely on dead wood 
or rocks. 
Found throughout North America. Known in some form in all of the grand 
divisions. 
4. Pertusaria pustulata (Ach.) Nyl. Act. Soc. Linn. Bord. 21: 441. 1856. 
Porina pustulata Ach. Lich. Univ. 309. 1810. 
Thallus thinner and smoother than that of the last, but becoming chinky or even 
somewhat verrucose, sea-green varying toward ashy, yellowish or brownish, often sub- 
orbicular, 2.5 to 4 em, across, or irregular and covering smaller areas of the substratum 
than that of the last, upper cortex as in the last and the thallus inclined to be partly 
hypophloeodal, or apparently more so than our other species; apothecia-containing 
verruce small, 0.4 to 1 mm. in diameter, only slightly raised; difform or becoming 
irregularly-hemispherical; apothecia | to 4 or 5 in each verruca, the black pores some- 
times becoming conspicuous and disk-like; hypothecium pale; hymenium pale below 
and commonly brownish above; paraphyses slender and commonly branched, some- 
what enlarged toward the apex; asci as in the last; spores oblong-ellipsoid, 50 to 135 p 
long and 25 to 56 » wide, 2 in each ascus. 
Well distributed over the State. On trees. 
Generally distributed over North America, but apparently not common toward the 
Pacific Coast. Known in all of the grand divisions. 
5. Pertusaria finkii Zahlbr. in Fink, Minn. Bot. Stud. 2: 696. 1901. 
Thallus thin and smooth or becoming chinky and somewhat verrucose, whitish in 
color, commonly occurring in small and somewhat irregular patches, scarcely more than 
1.5 tod em, across, without definite upper cortex; apothecia-containing verrucae small 
to middle-sized, 0.5 to 2mm. in diameter, flattened and rather inconspicuous; apothecia 
1 to about 5 in each verruca, the pores brown or blackish, or the apothecium becoming 
open and disk-like and of the same color; hypothecium pale; hymenium pale below 
and brownish above; paraphyses slender and somewhat coherent, simple or branched, 
rarely enlarged or darker toward the apex; asci clavate or cylindrico-clavate; spores 
oblong-ellipsoid, sometimes constricted along the sides, 70 to 140 » long, and 28 to 53 y« 
wide, 2, or rarely 1, in each ascus. 
