FINK—THE LICHENS OF MINNESOTA. 149 
lighter in color, attached to the substratum at a single point, the medullary layer 
well represented; small, 2.5 to 6 mm. in diameter; apothecia deeply sunken in 
minute pits, or becoming superficial and disk-shaped; spores rounded or oblong. 
No mature fruit has been found, and the spore and apothecial characters taken 
from Tuckerman. 
Collected on frequently wet rocks, at Morton, and reported as an Endocarpon. 
Elsewhere in North America from Massachusetts, Maryland, Arkansas, and Cali- 
fornia. Known also in Europe and Australia, 
2. Endocarpiscum polysporum (Tuck.) link. 
Heppia polyspora Tuck, Syn. N. A. Lich. 1: 115. 1882. 
Thallus foliose and closely attached to the substratum by means of numerous 
rhizoids, flat above or depressed with a raised margin, orbicular or irregular in form, 
small or very small, 1.5 to 4.5 mm. in diameter, smooth, olive-green or olivaceous, 
usually darker at the margin and below, the medullary layer represented by loosely 
arranged irregular cells, forming a tissue resembling the spongy parenchyma of leaves; 
apothecia immersed in the thallus, without thalloid exciple, the disk somewhat 
depressed and dark brown or black, very small, 0.2 to 0.5 mm. in diameter; hypothe- 
cium pale yellowish brown; hymenium pale below and yellowish brown above; par- 
aphyses very slender, commonly simple, frequently enlarged and brownish toward 
the apex; asci cylindrical, varying toward clavate or ellipsoid; spores subspherical, 
4 to 7 » the longest way. 
A few apothecia are larger, and the spores are also somewhat larger than Tucker- 
man’s plant showed. Possibly the plant should be separated from the present genus, 
but it can scarcely be placed with Heppia as was attempted by Tuckerman. 
Collected on earth at Granite Falls, 
Tuckerman’s plant was from Colorado, Nylander’s Heppia arenivaga from Japan 4 
appears to be the same plant. 
Heppia polyspora of the preliminary reports. 
HEPPIA Naeg. in Hepp. Spor. Flecht. Eur. pl. 7. f. 49. 1853. 
The thallus is distinctly foliose and closely attached to the substratum by means of 
rhizoids, though often rising more or less at the margins. The structure is peculiar 
in that the thallus is cellular throughout. The cells of three or more layers above 
are elongated horizontally and correspond to the usual upper cortex. Below this 
the cells are rather loosely arranged and elongated vertically, those midway between 
the upper and lower surfaces being most elongated and replacing a medullary layer. 
The cells of the lower portion are again less elongated and correspond somewhat to a 
lower cortex. The algal cells are scattered throughout the whole region of vertically 
elongated cells and even extend into the cortical regions. The algee are blue-green, 
but larger than those of Solorina and Pannaria, The cells are said to occur in chains, 
but this is difficult to make out. They are usually large, 14 to 22 mm. long. 
The apothecia are commonly immersed in the thallus, though in Heppia despreauxit 
they may be more or less raised. Tuckerman seems to have distinguished a thalloid 
exciple in certain raised apothecia of the above species, but such a structure is com- 
monly absent. The hypothecium and hymenium are pale or slightly colored. The 
paraphyses are commonly simple and somewhat coherent. The spores are simple. 
The resemblance of the present genus to Solorina in upper surface and disposition 
of apothecia, is not difficult of detection, but in the minute anatomy of the thallus 
we encounter very radical differences. The relation as to thallus is probably nearer 
to Endocarpiscum, though the algal cells are quite different. 
A single species occurs in the State. On calcareous soil. 
Type species [eppia urceolata Naeg. loc. cit. 
a Nyl. Lich. Jap. 104. 1890. 
