FINK—THE LICHENS OF MINNESOTA. 207 
at least seldom if ever sorediate, 5 to 17.5 em. long; apothecia chestnut-brown, 
plane or convex, small, 1 to 2 mm. in diameter; spores colorless (possibly becoming 
brownish), short-ellipsoid, 6 to 9 ~ long and 4 to 5 p wide. 
Ours sterile, and the data regarding apothecia taken principally from Nylander. 
Common in the northern portion of the State, the first subspecies being the only 
form thus far known farther south in Minnesota. However, the above-described form 
has been found in northeastern Iowa and doubtless occurs in southeastern Minnesota, 
Ours on trees, but on sandstone in Iowa. 
Distributed throughout North America, but usually confined to mountains south- 
ward. Usually sterile except in mountains or at the extreme north. Generally 
distributed throughout all the grand divisions. 
EXPLANATION OF PLATE 42.—A, Plant of Alectoria jubata on trunk of a balsam fir, showing the pendu- 
lous fruticose thallus. B, Plant of Usnea longissima hanging from the limb of a tree, containing strands 
several feet long. A natural size; B, about one-eighth natural size. 
la. Alectoria jubata chalybeiformis (L.) Ach. Lich. Univ. 593, 1810, 
Lichen chalybeiformis L. Sp. Pl. 1155. 1753. 
Thallus shorter, spreading, prostrate, or subpendulous, more rigid than the species, 
rather remotely and divaricately branched, flexuous, brown or brownish sea-green, 
commonly more or less sorediate, usually sparingly fibrillose, especially along the 
smaller branches, the fibrils frequently occurring several in a cluster, shorter than 
in the type, 15 to 85 mm. long. 
Ours is uniformly sterile, and no statement of apothecial characters could be found. 
Probably worthy of specific rank, but perhaps may best stand as a subspecies in the 
absence of spore characters, etc. 
The most common form in Minnesota and quite generally distributed over the 
State. On trees and no doubt yet to be found on rocks. 
Common throughout the northern United States, Alaska, and British America; 
fertile in mountains. Also distributed throughout northern Europe and Asia, 
1b. Alectoria jubata implexa (Ioffm.) Ach. Lich. Univ. 593. 1810. 
Usnea implexa Woffm. Deutsch. FI, 2: 134. 1795. 
Thallus pendent and slender, much branched and intertangled, elongated 10 to 
17.5 cm, long; brown throughout; apothecia not seen, 
Collected in the Misquah Hills and at Beaver Bay, once in each locality. On trees. 
Distributed throughout the Northern States and British America; fertile in 
mountains. Occurs also in Europe, though Nylander does not seem to recognize the 
subspecies. 
USNEA (Dill.) Adans. Fam. Pl. 2:7. 1763. 
The thallus is fruticose and frequently very long. Besides being the longest of 
lichen thalli, it shows the greatest specialization of the fruticose type. Branching is 
common, and the main trunks and the branches are usually cylindrical though rarely 
angular. A pseudocortex is developed on all sides of the cylindrical thallus. Inside 
of the quite thick cortex lies the algal layer in the form of a hollow cylinder. The 
medullary tissue within is dimorphic, the center consisting of a solid cylinder of 
densely packed hyph, extending in a longitudinal direction, and surrounding this 
a cylinder of loosely interwoven hyphe, uniting internally with the solid portion of 
the medullary tissue and externally with the cortex. The colors are sea-green or 
rarely straw-colored, varying to reddish brown, 
The apothecia are orbicular, most frequently terminal or subterminal on the 
branches, the disk pale in all of ours, usually flat and thin, the thalloid margin bearing 
fibrils. The hypothecium and the hymenium are both pale. The sporesare hyaline, 
simple, ellipsoid or rounded-ellipsoid, and scarcely differ enough in the various 
species to have much diagnostic value. 
