FINK—THE LICHENS OF MINNESOTA. 157 
narrower and laciniate, with usually more or less raised entire or crenate margins, 
frequently somewhat imbricate, smooth above or more or less isidioid-granulate, 
especially along the margins; upper surface brown, varying toward sea-green but 
seldom showing the reddish tendency of more southern specimens; lower surface 
paler and clothed with light brown or darker rhizoids, these forming a spongy nap in 
which are embedded the urceolate whitish cyphelle; apothecia usually submar- 
ginal, the disk reddish brown, the exciple thin, usually entire and finally losing its 
algal cells, middle-sized, 2 to 3 mm. in diameter; spores hyaline or pale, fusiform, 
4-celled, 30 to 32 » long and 8 to 9 » wide. 
Ours are uniformly sterile, and the above spore and apothecial characters are taken 
from Nylander. 
Confined to the northern portion of the State. Commonly on cedars in swamps, 
but sometimes on rocks or other trees. 
The plant is widely distributed in North America. Also known in all the grand 
divisions except Europe. 
7. Sticta scrobiculata (Scop.) Ach. Lich. Univ. 453. 1810. PLATE 28, 
Lichen scrobiculatus Scop. Fl. Carn. ed. 2. 384. 1772. 
Thallus somewhat loosely attached to the substratum, more or less orbicular in 
outline, middle-sized or larger, 4.5 to 15 cm. in diameter, smooth and scrobiculately 
pitted and clothed more cr less with grayish soredia, sea-green, varying toward yel- 
low, the lobes short and rounded with undulate or crenate margins, below clothed 
with usually dark rhizoids, giving a villous surface interspersed here and there with 
light naked spots, these resembling somewhat in appearance the cyphellze of our other 
Stictas; apothecia scattered, small to middle-sized, sessile, the disk reddish brown, 
the margin entire; hypothecium rather indistinctly 2-layered, the upper layer 
thinner and brownish, the lower wider and pale; hymenium pale or brownish; 
paraphyses frequently branched, the apex often enlarged and brownish; asci ovate- 
clavate; spores long-fusiform, 4 to 8-celled, hyaline or pale, 50 to 75 » long and 5 to 
7 » wide. 
Ours are always sterile, and the spore and apothecial characters were taken from 
European specimens. 
Found only along the north shore of Lake Superior. On mossy rocks or on trees. 
Frequent in New England and northward throughout the eastern half of British 
America and found also in Alaska. Known also in Europe, Asia, and Africa. 
EXPLANATION OF PLATE 28.—Plant on a mossy trunk, showing the characteristic lobed and pitted thal- 
lus. Natural size. 
Family PELTIGERACEAE. 
The family as represented in our flora includes three genera, of which Peltigera 
may be regarded as the most typical. In this there isa total absence of lower cortex, 
though the species are usually large and have foliose thalli not more closely attached 
to the substratum than are members of the Stictaceae. Iowever, in the genus named 
above, the lower cortex is more or less replaced by a layer of hyph running hori- 
zontally below the medullary layer. The trichomatic hyphz are also usually pres- 
ent in the species. In one of the other two genera, Solorina, the lower cortex is 
scarcely developed, but in the other, Nephroma, it is well developed. Solorina is 
thus more nearly typical as regards the cortex, but the genus is somewhat aberrant 
in that the apothecia are scattered over the upper surface of the thallus and not con- 
fined to the lobes as in the other two genera. In Nephroma there is a well developed 
cortex below, and in this respect the genus is the highest member of the family. 
The apothecia of Nephroma are typical of the family in that they are immersed in 
the lobes, but their location is peculiar in being removed to the lower side of the 
lobes, 
