FINK—THE LICHENS OF MINNESOTA. 203 
The plants occur on trees, old wood, and rarely on rocks. 
Type species Hvernia prunastri (L.) Ach. loc. cit. 
KEY TO THE SPECIES. 
Thallus commonly sorediate and frequently isidioid, pale below.. 2. FE. prunastri. 
Thallus not sorediate, but usually softish isidioid (furfuraceous), 
for the most part black or black-spotted below................ 1. £. furfuracea. 
1. Evernia furfuracea (L.) Mann. Lich. Bohem. 105. 1826. 
Lichen furfuraceus L. Sp. Pl. 1146. 1758. 
Thallus fruticose or subfoliose, 15 to 60 mm. long in our Minnesota specimens, though 
the species is frequently much longer, ascending, prostrate or pendulous, compressed , 
dichotomously and subpinnately lobed, the lobes tufted and frequently long, usually 
covered more or less with soft isidioid branchlets or tubercles above (furfuraceous), 
commonly channeled and lacunose below; sea-green to grayish above, beneath whit- 
ish, black-spotted or for most part black; apothecia rather large, 2 to 12 mm. in diam- 
eter, frequently short-pedicellate, terminal or lateral, disk deeply concave and brown, 
the margin usually entire but somewhat irregular; hypothecium pale; hymenium 
brownish above, pale brownish or pale below; paraphyses simple or rarely branched, 
with apex pale and scarcely thickened; asci clavate; spores 6.5 to 7.5 «long and 4 to5 
wide, oblong-ellipsoid. 
Occurring rarely in the northeastern portion of the State. On cedars. Ours sterile. 
The species occurs in the northern United States and Canada and southward in the 
mountains. Alsoreported from Florida by Calkins. Known in cold portions of all the 
grand divisions except Australia. 
2. Evernia prunastri (L.) Ach. Lich. Univ. 442. pl. 10. f. 1. 1810. PLATE 39. 
Lichen prunastri L. Sp. Pl. 1147. 1753. 
Thallus fruticose, tufted, ascending, prostrate, or long and pendent, rounded, some- 
what angular or flattened, sometimes channeled below, much branched dichoto- 
mously and divaricately, the branches sometimes becoming long, lacunose, commonly 
more or less sorediate and frequently bearing isidioid branchlets, straw-colored to pale 
sea-ereen or paler below, 15 to 85 mm. long; apothecia of medium size in the two 
fruited specimens from the State, 4 to 8 mm. in diameter, sessile or subpedicellate on 
the margins of the branches, concave, the disk brown and the thalloid margin entire; 
hypothecium pale; hymenium brownish above and pale brownish below; paraphyses 
simple or possibly rarely branched, apex pale and scarcely thickened; asci clavate; 
spores ellipsoid, 55 to7 pe long and 3 to 4» wide. 
Generally distributed over the State, but hardly common. On trees, old wood, and 
rarely on rocks. Found fruited but twice. 
Occurs throughout the northern United States and British America. The plant is 
known in all the grand divisions except, possibly, Australia. 
EXPLANATION OF PLATE 39.—Plant on the limb of a tree showing the fruticose thallus and the very rare 
apothecia. Natural size. 
RAMALINA Ach. Lich. Univ. 122, 598. pl. Di. f. 5-71, 1810. 
Pirate 40. 
The thallus is fruticose and flattened. The pseudocortex consists of closely packed 
hyphie, extending wholly or for the most part in the direction of the long axis of the 
thallus. The medullary portion consists of loosely interwoven hyphee which, in some 
species, run mostly in the direction of the long axis of the thallus and arc seldom 
united with the cortical hyphi, while in other species (all of ours) they run in various 
directions and are commonly united with the cortical hyphw. The algal layer extends 
around wholly within the cortex in the form of a hollow flattened cylinder. 
The apothecia are upon one side of the thallus (upper when the branches are not 
erect), along the margin or terminal or subterminal, subpedicellate, with entire 
