138 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
4. Collema limosum Ach. Lich. Suec. 126, 236. 1798. 
Lichen limosus Ach. Lich. Suec. 126. 1798. 
Thallus thin, in ours usually consisting of scattered and inconspicuous greenish to 
olivaceous squamules, these usually more or less obscured by the apothecia, sometimes 
becoming larger and lobate, the lobes then dentate-crenate or narrowed into ascending, 
blunt lobules; rhizoids few, the algal cells more numerous toward the top and bottom 
of the thallus, when best developed, rather smaller than those of the last; apothecia 
commonly immersed, but becoming superficial, smallish or becoming larger than in 
the last, 1 to 3 mm. in diameter, the disk reddish brown, usually flat, the thalloid 
margin rather thin and prominent; hypothecium brownish; hymenium pale below 
and brownish above; paraphyses simple or rarely branched, enlarged and brownish 
toward the apex; asci clavate; spores pale, muriform-multilocular, 23 to 37 long 
and 10 to 14» wide, commonly 4 in each ascus. 
Collected at Bemidji and at Koochiching. On earth. 
Distributed across North America, but not known in the southern portion of the 
United States. Known also in Europe and Asia. 
5. Collema plicatile Ach. Lich. Suec. 129, 237. 1798. 
Lichen plicatilis Ach. Vet. Akad. Handl. 16: 11. pl. 1. f. 2. 1795. 
Thallus irregular or suborbicular, small, ours from 5 to 25 mm. in diameter, rather 
thicker than that of the last two, the more or less imbricated lobes usually ascending 
or erect with plicate-crisped margins, dark-green or more commonly blackening, or 
rarely dark olivaceous and scarcely lighter below; rhizoids very few and the thallus 
only attached toward the center or at one side; algal cells more numerous toward the 
top or in the more erect portions toward both surfaces; apothecia small, 0.4 to 1 mm. in 
diameter, frequently short-pedicellate, the disk brown and darkening, commonly 
more or less concave, the margin entire; hypothecium brownish; hymenium pale 
below and brownish above; paraphyses simple or rarely branched, commonly en- 
larged and brownish toward the top; asci clavate; spores ovoid-ellipsoid, pale, more 
or less muriform, 18 to 28 » long and 6 to 8 » wide. 
Collected at Mankato. On calcareous rocks. 
The species was reported from Iceland by Tuckerman, and H..E. Hasse records it 
from California, The writer has found it also in Iowa. The specimens so reported 
are in each case differently named. The synonymy must at best be regarded as very 
uncertain. Known also in Europe and Africa. 
6. Collema furvum Ach. Lich. Suec. 132, 236. 1798. 
Lichen furvus Ach. Lich. Suec. 132. 1798. > 
Thallus orbicular or irregular, small or middle-sized, 10 to 50 mm. in diameter, 
frequently scattered or the central portions falling away, olivaceous-green and blacken- 
ing, usually somewhat lighter below, the upper surface becoming covered with 
granules of the same color as itself, the lobes rounded or somewhat irregular, with 
entire, undulate or crenulate and more or less crisped margins, frequently becoming 
somewhat elongated, ascending or suberect; attachment of thallus much as in the last, 
or more of the lower surface adhering to the substratum; algal cells somewhat more 
numerous toward the upper side; apothecia usually few and scattered, small, 0.5 to 
1 mm. in diameter, sessile, the disk brown and darkening, flat or concave, the thalloid 
margin entire; hypothecium brownish; hymenium pale or pale brownish below and 
brownish above; paraphyses simple or rarely branched, frequently enlarged and 
brownish toward the apex; asci clavate; spores hyaline or pale, ellipsoid, 4-celled 
and becoming muriform, 18 to 26 » long and 8 to 12 » wide. 
Collected twice along the north shore of Lake Superior and in several places in the 
southwestern portion of the State. The material from the Lake Superior region has 
smaller, more erect lobes, more numerous apothecia, and narrower spores. However, 
it agrees well with some of Arnold’s European material. On various rocks. 
