FINK—THE LICHENS OF MINNESOTA. 197 
According to Tuckerman confined for the most part to mountains and only reported 
by him in the mountains of New England. Has been reported from Ohio more recently 
and also from Alaska. Known in all of the grand divisions except Africa. 
EXPLANATION OF PLATE 38.—Plant on a tree trunk, showing the pertuse foliose thallus. Natural size. 
10. Parmelia aleurites Ach. Meth. Lich. 208. 1803. 
Lichen aleurites Ach. Lich, Suec. 117. 1798. 
Thallus rather small, 35 to 85 mm. in diameter or variously broken and spread over 
larger areas of the substratum, whitish or light sea-green, closely adnate, rugose and 
more or less sorediate, dark-colored and sparingly fibrillose below, the margin some- 
times raised or ascending; apothecia chestnut-brown or chestnut-reddish, 1 to 3 mm. 
in diameter; spores oblong or oblong-fusiform, often curved, 11 to 12 » long and 3 to 
4 wide. 
Ours sterile, the spore and apothecial characters taken from Nylander. 
This is evidently the plant which Tuckerman did not distinguish from Parmelia 
ambigua albescens Wahl., but which Nylander recognized.2 Strangely enough 
Cetraria aleurites (Ach.) Th. Fr.b can also be traced back to Lichen aleurites Ach. 
That two distinct plants are based on this plant of Acharius may be seen plainly by 
comparing Cetraria aleurites of Tuck.¢ with / -armelia aleurites of Nylander’s work cited 
above. 
On trees at Minneapolis and on rocks at New Ulm. 
Elsewhere in North America from Greenland. Known also in Europe. 
11. Parmelia olivacea (L.) Ach. Meth. Lich. 213, 1803. 
Lichen olivaceus LL. Sp. Pl. 1148, 1753. 
Thallus small or medium-sized, 20 to 80 mm. in diameter, closely adnate, the upper 
surface usually somewhat rugose and frequently bearing isidioid growths, pale or 
darker olivaceous, the lobes more or less radiate, frequently somewhat imbricate, 
more or less branched, their margins sinuate or obscurely crenate; beneath of the same 
color or more commonly black, bearing scattered brown or black rhizoids; apothecia 
small or middle-sized, 2 to 6 mm. in diameter, sessile or rarely subpedicellate, the 
disk chestnut or darker, the margin entire or crenulate, concave or rarely plane, 
hypothecium pale; hymenium pale or brownish, especially above; paraphyses simple 
and slender, the apex usually brownish and somewhat thickened; asci clavate; 
spores ellipsoid, 11 to 16» long and 7 to 9 wide. 
Distributed throughout the State and common in the northern portion. On trees 
and old wood. 
Common in the Northern States and northward; occurring farther south, but there 
confined mostly to mountains, Common in northern Europe and Asia and also found 
in northern Africa. 
lla. Parmelia olivacea aspidota Ach. Meth. Lich. 214. 1803. 
Thallus, and apothecia externally, thickly covered with minute verrucee of the 
same color; spores smaller, 7 to 9 » long and 5 to 6 y wide; paraphyses more distinct 
in the material examined. Otherwise the same microscopically. 
Collected in the Leaf Hills near Vining. On trees, Doubtless occurs in other parts 
of the State. 
North American distribution about the same as that of the species. Also occurs 
with the species in Europe. 
«Cf, Nyl. Not, Sillsk. Faun, Plor. Penn. 5:105, 1861. 
b Lich. Scand. 1: 109. 1871. 
eSyn. N. A, Lich, 1:32. 1882, 
