FINK—THE LICHENS OF MINNESOTA, 235 
seen in the last; apothecia somewhat larger than in the last and not so completely 
immersed, the perithecium blackish-brown, the amphithecium pale or becoming 
brownish; asci clavate, or cylindrico-clavate; spores ellipsoid, larger than in the last, 
15 to 24 long and 6 to 10” wide. 
Distribution and habitat in the State the same as in the last. 
Elsewhere in North America in New England, New York, Pennsylvania, Louisi- 
ana, Ohio, Illinois, lowa, California, and Canada. Known also in Europe and Africa. 
4a. Verrucaria nigrescens viridula (Schrad.) Nyl. Mém. Soc. Acad. Maine et Loire 
4: 23. 1858. Puate 49, A. 
Endocar pon viridulum Schrad. Spic. Fl. Germ, 192. pl. 2. f. 4. 1794. 
Thallus olivaceous-greenish; spores larger, 20 to 32 long and 10 to 13. wide. 
Widely distributed in the extreme northern portion of the State, probably being 
the common form upon the rocks of the region, while the species is common upon 
the calcareous rocks farther south, 
Elsewhere in North America in I|linois and California. Known also in Europe, 
Asia, and Africa. 
Verrucaria viridula and Verrucaria viridula subfuscella of the preliminary reports. 
EXPLANATION OF PLATE 49.—A, Plant of Verrucaria nigrescens viridula on rocks, showing the apothecia 
in raised spots in the thallus. B, Plant of Pyrenula leucoplaca, showing the thin whitish epiphloodal 
film of thallus and the apothecia partly embedded in the woody substratum. A enlarged 3} diameters; 
B, 33 diameters. 
Family PYRENULACEAE. 
The family is represented in our flora by the three genera Sagedia, Arthopyrenia; 
and Pyrenula. The thallus is crustose in all three and is rather better developed in 
the first genus than in the second and third, being there more often above the sub- 
stratum and rather less frequently disappearing. However, in the last genus we find 
the higher spore development on the whole, and Pyrenula must consequently be 
regarded as the highest genus. 
The paraphyses are better developed than in the Verrucariaceae, being longer and 
commonly remaining distinct, and the spores are as a whole of a higher type, ranging 
from 2-celled to muriform conditions and frequently showing color. In addition to 
the statement made in the description of the Verrucariaceae concerning the propriety 
of separating the present family from that may be added that the algal symbiont is 
different in the two families, being Pleurococcus in the Verrucariaceae and Chroolepus 
in the present family. This of itself may have little weight, but is worthy of con- 
sideration in connection with other differences. For the remainder of the argument 
the reader is referred to the description of the Verrucariaceae, The Pyrenulaceae are 
also somewhat closely related to the Pertusariaceae. 
SAGEDIA Ach. Lich. Univ. 71, 327. pl. 6. f. 8-7. 1810. 
The thallus is crustose, thin, smooth, slightly roughened, granulose, scurfy, chinky, 
subareolate, or even mainly or wholly hypophloeodal or disappearing. The struc- 
ture is rudimentary without differentiation into layers, and the color varies from 
ashy through shades of greenish to brown or even blackish brown, The algal symbiont 
is apparently similar to that of the Pyrenulas and Arthopyrenias, but little could be 
made out in the scant thalli examiried. 
The apothecia may be quite superficial or more or less immersed in the thallus or 
substratum and are globose and inclosed in the exciple (perithecium), which is dark 
in color and well developed. The amphithecium is pale. The paraphyses are very 
slender and commonly distinct. The spores are hyaline, 4 to several-celled, and 
fusiform to acicular. 
The genus is closely related to Verrucaria, Arthopyrenia, and Pyrenula, differing 
mainly in the spore characters, the more commonly distinct paraphyses, and the per- 
sistently pale amphithecium. 
