FINK—THE LICHENS OF MINNESOTA. 137 
the center where the thallus is thicker, the margins somewhat explanate, the central 
lobes frequently reduced to mere granules; leek-green, olivaceous, or blackening 
above and scarcely lighter below; rhizoids few and weak; algal cells quite prom- 
inently aggregated toward the top and bottom of the thallus; apothecia small or mid- 
dle-sized, adnate or more or less immersed, 0.75 to 2.5 mm. in diameter, the disk com- 
monly flat or concave, reddish brown, the thalloid margin entire or rarely crenate; 
hypothecium pale or brownish; hymenium pale below and pale brownish above; 
paraphyses simple or rarely branched, commonly enlarged and brownish toward the 
apex; asci clavate; spores ovoid-ellipsoid, from 4-celled becoming somewhat muri- 
form, pale or hyaline, 17 to 25 » long and 8 to 12 ” wide. 
Generally distributed over the State. On earth or mossy rocks, more common in 
calcareous regions. 
Widely distributed in North America, and still not reported from a large number of 
localities. Known also in Asia, Europe, and Africa. 
2. Collema tenax (Sw.) Ach. Lich. Suec. 128, 237. 1798. 
Lichen tenax Sw. Nov. Act. Soc. Sci. Ups. 4: 249. 1784. 
Thallus usually more or less orbicular, rather thin, the lobes expanded and closely 
adnate, or rarely becoming more or less raised and complicate, yellowish-green or dark- 
ening; rhizoids as in the last, but the algal cells less distinctly aggregated toward the 
top and bottom of the thallus; plant commonly of about the same size as the last, but 
the thallus of ours usually very small and poorly developed; apothecia smallish, 0.5 to 
2mm. in diameter, commonly more or less immersed in the thallus, the disk usually 
flat or concave, reddish brown, the thalloid margin entire or crenate; hypothecium 
brownish; hymenium pale below and brownish above; paraphyses simple or rarely 
branched, commonly thickened and brownish toward the apex; asci clavate; spores 
as in the last. 
Hardly more than a subspecies of the last. 
A single collection has been made in the State at Mankato. On earth. 
Distributed throughout the eastern half of the United States and northward into 
British America. Known also in Europe. 
3. Collema crispum (Huds.) Hoffm. Deutsch. Fl. 2: 101. 1795. 
Lichen crispus Huds. Fl. Angl. 447. 1762. 
Thallus more or less orbicular, in ours smallish, 15 to30 mm. in diameter, rather thin, 
the marginal lobes somewhat expanded, those of the center with raised plicate and 
dentate-granulate edges; olivaceous varying toward green or darker color; rhizoids 
few and the thallus adhering to the substratum; algal cells more or less aggregated 
toward the top and bottom of the thallus; apothecia frequently numerous and nearly 
concealing the central portion of the thallus, small or middle-sized, 0.8 to 2.5 mm. in 
diameter, less inclined to be immersed, the disk more or less concave, dark reddish 
brown, the margin crenate-granulate or more rarely entire; hypothecium brownish; 
hymenium pale below and brownish above; paraphyses simple or rarely branched, 
commonly enlarged and brownish toward the apex; asci clavate; spores oblong- 
ellipsoid, pale or hyaline, from 4-celled becoming more or less muriform, 16 to 30 p 
long and 8 to 12 » wide. 
The apothecia are deeply concave in ours. Like the last, the present is closely 
related to the first species, of which it may be regarded as a subspecies. 
Collected at Bemidji and on the islands belonging to the United States in Lake of 
the Woods. On earth. 
Throughout the northern half of the United States from Colorado eastward, and 
extending across the continent in British America. Knownalso in Europe, where it is 
usually regarded as a form of Collema pulposum. 
7920—10——10 
