FINK—THE LICHENS OF MINNESOTA. 83 
1. Biatorina tricolor (With.) Fink. 
Lichen tricolor With. Arr. Brit. Pl. ed. 3: 20. 1796. 
Thallus composed of very minute granules, these commonly running together to form 
a thin, more or less chinky or obscurely rugose-verrucose, ashy crust, continuously 
widespread over the substratum or more or less scattered; apothecia small or minute, 
in ours 0.15 to 0.25 mm. in diameter, adnate, the disk flat or slightly convex, flesh- 
colored passing through shades of brown to blackish, the paler exciple sometimes dis- 
appearing (disk said by Tuckerman to be pruinose); hypothecium pale or yellowish; 
hymenium pale throughout, or sometimes brownish above; paraphyses commonly 
simple, the apex frequently somewhat thickened and brownish; asci clavate or cylin- 
drico-clavate; spores oblong, varying toward ellipsoid or fusiform, and sometimes 
more or less curved, 9 to 15 » long and 3 to 4.5 » wide. 
Generally distributed over the northern portion of the State. On trees, especially 
on poplars. Both this and the next two are easily confused with Arthonia patellu- 
lata, which most commonly grows on the same substratum, 
Widely distributed in the northern United States and northward to arctic America, 
also found in Florida and southern California. Known also in Europe and Africa. 
Biatora mixta is the synonym used in the preliminary reports. 
la. Biatorina tricolor atlantica (Tuck.) Fink. 
Biatora mixta atlantica Tuck. Syn. N. A. Lich. 2: 30. 1888. 
Thallus as in the above, as is also the whole external appearance; internally differ- 
ing in that the spores are frequently, and in some specimens commonly, simple. 
The plant is littlke known, and it may possibly represent immature conditions. If 
not, it is an interesting connecting form between the present genus and Lecidea. 
Collected at Battle Lake. On poplars. 
Elsewhere noted only in New England. 
Biatora mixta atlantica is the synonym used in the preliminary reports, 
2. Biatorina atropurpurea (Schaer.) Mass. Ric. Lich. 135. /. 265. 1852. 
Lecidea sphaeroides atropurpurea Schaer. Enum. Lich. Eur. 140. 1850. 
Thallus composed of very minute granules, these usually running together to form 
a somewhat chinky or leprose, widespread, thin, and rarely more or less sorediate 
crust, ashy in color, varying toward greenish or brownish and sometimes disappear- 
ing; apothecia small or minute, 0.18 to 0.35 mm. in diameter, adnate or slightly 
immersed in the thin thallus, the disk flat to strongly convex, the exciple disap- 
pearing early in ours, and the ofttimes immersed apothecia having thus a falsely 
lecanoroid appearance, brown and varying toward blackish; hypothecium pale or 
pale brownish; hymenium pale or pale brownish below and darker above; paraphy- 
ses commonly simple, usually somewhat thickened and brownish toward the apex, 
asci cylindrico-clavate; spores ellipsoid, 10 to 16 » long and 3.5 to 6 w wide. 
Spores somewhat narrower, exciple more evanescent, and apothecia smaller than 
in the plant as described by Tuckerman and Th. Fries, and our plant on the whole 
perhaps intermediate between theirs and the last above, 
Throughout the northern portion of the State. On trees, especially on poplars. 
Reported also from New England, Illinois, Florida, California, and points north- 
ward through eastern British America to Newfoundland. Well known also in Europe, 
but further distribution scarcely to be ascertained in the present state of synonomy, 
Biatora atropurpurea of the preliminary reports. 
3. Biatorina heerii (Hepp) Fink. 
Biatora heerii Hepp, Spor. Flecht. Eur. pl. 16. f. 135. 1853. 
Thallus composed of very minute rounded and frequently heaped granules, some- 
times visible with a lens, often seen only in sections, rarely disappearing entirely ; apo- 
thecia minute, 0.1 to 0.2 mm. in diameter, sessile or adnate, flesh-colored and black- 
