FINK—-THE LICHENS OF MINNESOTA. 169 
As in Gyrophora, the apothecia frequently occur in groups, and each group is 
frequently considered a single apothecium. The individual apothecia are usually 
rounded instead of elongate. The spores are many-celled and muriform, commonly 
brown, though they may be pale. A single spore usually occupies each ascus, though 
two sometimes occur together. 
The genus has a single representative within the State. 
Ours and the other American species occur on rocks. 
Type species Umbilicaria exasperata (Gunn.) Hoffm. loc. cit. 
1. Umbilicaria pustulata (L.) Hoffm. Descr. Pl. Crypt. 2: 13. pl.28. f. 1-2. pl. 
29. f. 4. 1794. 
Lichen pustulatus L. Sp. Pl. 1150. 1753. 
Thallus rounded or irregular in form, the edges more or less irregular and sometimes 
irregularly lobed, usually of middle size, 3 to 15 cm. in diameter; prominently 
papulose or pustulate, occurring singly, brown or brownish ash-colored, sometimes 
more or less powdery, beneath grayish to brownish, granulate, lacunosely pitted; 
apothecia sometimes single but more commonly in groups, these considerably raised, 
black and more or less rounded, 0.5 to 2 mm. in diameter, the largest clusters seldom 
conta*ning more than 12 to 15 apothecia; the individual apothecium usually rounded 
and concave and when alone reaching 0.5 mm, in diameter, or even 1 mm. in foreign 
specimens; hypothecium pale brownish to brown; hymenium brownish; paraphyses 
frequently branched both near the apex and farther back, the apex commonly thick- 
ened and brownish; asci broadly-clavate; spores ellipsoid or oblong-ellipsoid, brown 
or sometimes pale, 48 to 70 » long and 22 to 38 »# wide. 
The subspecies Umbilicaria pustulata papulosa (Ach.) Tuck.@ has been recorded for 
the State, but there are scarcely two distinct forms in Minnesota. Possibly ours is 
all nearer the subspecies; it surely is so in color, Tuckerman giving ashy gray as the 
color of the species. 
Found throughout the extreme northern portion of the State, but rare. On rocks. 
Distributed throughout the eastern side of North America, especially in the moun- 
tains. Also in Texas and New Mexico. Known in all of the grand divisions ex- 
cept Australia. 
Family LECANORACEAE. 
The family as represented in our flora consists of the three genera, Acarospora, 
Lecanora, and Haematomma. The family thus limited seems natural enough, but is 
closely related to the Parmeliaceae, the close relationship appearing most plainly in 
the few foliose Lecanoras, such as L. rubina and L. muralis. However, even in these 
two species, the thallus is closely adnate and scarcely more than subfoliose, while in 
the Parmeliaceae the thalli are always plainly foliose or fruticose. 
Thus it appears that the present family is most closely related to the Parmeliaceae, 
and Schneider has seen fit to unite the two families. But there are other relationships 
of the Lecanoraceae, as already mentioned, viz, with the Baeomycetaceae through 
Iemadophila and with certain Lecideaceae which show some indication of a thalloid 
exciple. 
In the present family the thallus is commonly crustose, but a few of the species of 
Lecanora possess subfoliose thalli. The algal symbiont is commonly Cystococcus, 
but Pleurococcus seems to occur instead in the Acarosporas. The apothecia vary as 
to position from sessile to immersed, and the thalloid exciple is plainly evident and 
commonly persistent in all superficial apothecia. The spores are always hyaline and 
never muriform, but they vary considerably within these limitations. 
The family is large, the genus Lecanora being one of the largest in our flora. 
“Syn. Lich, N, E, 70, 1848, 
7920—10—— 12 
