FINK—THE LICHENS OF MINNESOTA. 195 
Common throughout the United States, Alaska, and British America. Distributed 
in all of the grand divisions. 
EXPLANATION OF PLATE 36.—A, Plant of Parmelia tiliacea on a tree trunk, showing the closely attached 
foliose thallus and the sessile apothecia. B, Plant of Cetraria juniperina pinastri on birch bark, showing 
the crisped ascendant thallus lobes. A enlarged 13 diameters; B, 1} diameters. 
6. Parmelia borreri Turn. Trans. Linn, Soc. Lond. 9: 148. pl. 13. f. 2. 1808. 
Thallus rather closely adnate with a sometimes free and slightly raised margin, 
rather large, 6 to 14.5 cm. in diameter, the upper surface sea-green or varying toward 
ashy or brownish, commonly rugose, rarely sorediate (more commonly so in European 
specimens), the margins rarely white-powdery, the lobes rather wider and shorter 
than in the next and usually cut crenate; lower surface ashy to pale brownish with 
white or darkening rhizoids; apothecia middle-sized to large, 3 to 14 mm, in diameter, 
loosely sessile, the disk chestnut and the margin entire, crenulate, or irregular, usu- 
ally deeply concave or the smaller ones even cyathiform; hypothecium pale or 
brownish; hymenium pale or yellowish below and brownish above; paraphyses rather 
indistinct, but simple and slender, with tips usually brownish and thickened; asci 
clavate; spores ellipsoid, 10 to 16 » long and 6 to 8.5 » wide. 
Widely distributed in the State, but scarcely common. Represented in the north- 
eastern portion by the subspecies below. On trees and rarely on rocks. 
Seems to be widely distributed in North America, though Tuckerman thought the 
first subspecies much more common and did not differentiate clearly as to distribu- 
tion. Known in all the grand divisions except Australia. 
6a. Parmelia borreri rudecta (Ach.) Tuck. Syn. Lich. N. E. 26. 1848. 
Parmelia rudecta Ach. Syn. Meth. Lich. 197. 1814. 
Thallus covered with isidioid branchlets or rarely mere granules, on the whole 
rather lighter-colored than the above, rarely fruited, and when so the apothecia 
small, those seen not exceeding 3 or 4 mm. in diameter. 
Distributed throughout the State, but not more common than the species. On trees 
and rarely on rocks; most common on cedars in swamps in the northern portion of 
the State. 
Distributed throughout North America and found also in Australia. 
7. Parmelia saxatilis (L.) Ach. Meth. Lich. 204. 1803. PiaTE 37. 
Lichen saxatilis L.. Sp. Pl. 1142. 1753. 
Thallus rather less closely adnate than the last and smooth or obscurely rugose, 
becoming rimose, often bearing isidioid granules or branchlets, sea-green or ashy, 
the lobes commonly long and narrow and sinuate or subdichotomously branched, 
somewhat imbricate, rather smaller than the last, 6 to 13.5 cm. in diameter (but 
reaching 17.5 cm. in rare instances), beneath black, or brownish toward the margins, 
and clothed with black rhizoids; apothecia rarely present, middle-sized to large, 3 
to 12 mm. in diameter, sessile or subsessile, the disk chestnut, the margin entire, 
crenulate or irregular, concave or the smaller ones cyathiform; hypothecium and 
hymenium pale or yellowish; paraphyses commonly simple and slender, the apices 
usually brownish and thickened; asci clavate; spores ellipsoid, 12 to 16 » long and 
8 to 10 » wide. 
Distributed throughout the State, but rarely fruited. On trees, old wood, and rocks. 
Best developed in northern Minnesota, where the plant is oftener found fruited. 
Common in northern United States and northward, but rare southward. Known 
in all of the grand divisions. 
EXPLANATION OF PLATE 37.--Parmelia saratilis and P. physodes taking possession of an old balsam fir. 
At Grand Marais. About one-twelfth natural size. 
