FINK—THE LICHENS OF MINNESOTA. 229 
in diameter, sessile or subsessile, the disk flat or slightly concave, commonly whitish- 
pruinose but sometimes naked and dark brown, the margin entire or crenulate; hypo- 
thecium pale or yellowish; hymenium pale below and brownish above; paraphyses 
simple, or branched toward the usually enlarged and brownish apex; asci clavate; 
spores oblong-ellipsoid, 12 to 18 » long and 6 to 9 » wide. 
Common in the northern portion of the State, but usually sterile. On trees and 
rarely on rocks. 
Distributed throughout the northern United States, in cold portions, and British 
America. Known also in Europe and Africa. 
9. Physcia caesia (Hoffm.) Nyl. Act. Soc. Linn. Bord. 21: 308. 1856. 
Lichen caesius Uoffm. Enum. Lich. leon. 65. pl. 12. f. 1. 1784. 
Thallus medium-sized, 18 to 80 mm. in diameter, closely adnate, stellate, the upper 
surface bearing rounded gray soredia, the lobes usually quite elongated and branched, 
the ends rounded or crenate, more or less imbricated; light sea-green, beneath whitish 
or rarely blackening with usually dark rhizoids; apothecia small, 1.5 to 4 mm. in 
diameter, sessile, the disk flat or slightly concave, dark brown to black or rarely gray- 
pruinose, the margin entire or crenulate; spores 15 to 23 » long and 8 to 12 » wide. 
Ours rarely fruited, the apothecial and spore characters taken from Tuckerman. 
No doubt generally distributed over the State, some of the material referred to 
Physcia granulifera in the first four papers of the preliminary survey belonging here. 
On the other hand, some of the specimens referred to here in the same pzpers will 
have to be placed elsewhere eventually, as they are small, narrow-lobed plants 
and usually devoid of sordeia. On rocks and rarely on trees. 
No doubt generally distributed over northern United States, at least east of the 
Rocky Mountains, and extending into British America and Alaska, but little known 
and confused with other species. Also known in Europe, Asia, and Africa. 
10. Physcia obscura (Schaer.) Nyl. Act. Soc. Linn. Bord. 21: 309. 1856, 
Parmelia obscura Schaer. Enum. Lich. Eur. 36. 1850. 
Thallus closely adnate except on mosses, commonly stellate, the upper surface 
smooth or rarely roughened, rarely sorediate, the lobes commonly long and dichoto- 
mously much branched, the ends rounded or crenate, more or less imbricated and 
frequently passing toward the center into a subcontinuous crust usually composed 
of closely packed and imbricated lobules, rarely ciliate along the margins; sea-green 
varying toward brownish or more rarely toward ash-color, middle-sized, 20 to 80 
mm. in diameter, beneath black with black rhizoids or the surface and rhizoids 
rarely lighter-colored; apothecia small or rarely larger, 1.5 to 4 mm, in diameter, 
sessile, the disk flat or slightly concave, reddish brown to black, or possibly rarely 
subpruinose, the margin entire or rarely crenulate, the lower side or rarely the whole 
outer surface of the exciple more or less ciliate; hypothecium brownish; hymenium 
pale, or brownish above; paraphyses slender, simple or branched toward the usually 
thickened and brownish apex; asci clavate; spores oblong ‘to ellipsoid, 17 to 24 
long and 8.5 to 12 » wide. 
Generally distributed over the State. On trees, rocks, and old wood, and over 
mosses. 
Found in all portions of North America in some form. Known in all the grand 
divisions. 
10a. Physcia obscura endochrysea (Hampe) Nyl. Act. Soc. Sci. Fenn. 7: 440. 1863 
Parmelia endochrysea Hampe; Nyl. Syn. Meth. Lich. 1: 427, 1858. 
Thallus more or less saffron-colored within, the peculiar coloration frequently 
extending to the hypothecium and the thalloid exciple, but seldom to the hymenium. 
Collected on rocks at Rainy Lake City, Harding, and Tower. Doubtless more 
widely distributed in the northern portion of the State. 
