FINK—THE LICHENS OF MINNESOTA. 241 
the ampithecium pale; paraphyses but rarely distinct, slender, sometimes branched 
at the frequently more or less enlarged and colored apex; asci cylindrico-clavate; 
spores 2-celled, oblong-ellipsoid, 12 to 18» long and 5 to 7» wide, 
The spore measurements given are little more than half as large as those of Nylan- 
der;@ yet ours seems to be the view of Tuckerman, who states that the spores are 
smaller than in Pyrenula punctiformis.® 
Collected at Minneapolis, at Mankato, and at Beaudette. These widely separate 
localities would seem to indicate that the plant is generally distributed over the 
State. On birch bark, and easily mistaken for other Pyrenulas or Sagedia oxyspora. 
Elsewhere in North America in New England, North Carolina, South Carolina, 
Alabama, Florida, Ohio, Hlinois, lowa, and Missouri. Found also in South America. 
Family DERMATOCARPACEAE. 
The family rests upon the characters of the genus Dermatocarpon, in which we have 
a foliose or a squamulose-foliose thallus and apothecia completely immersed in the 
thallus and indicated at the surface only by an ostiole. With the complete immersion, 
the perithecium has become abortive, and we have scarcely more than a colorless or 
slightly colored amphithecium surrounding the hymenium, It is upon this difference 
in thallus structure and the accompanying variation in apothecial development that 
the separation of the present family from the closely related Verrucariaceae must rest. 
The spores are simple in both genera, thus resembling Verrucaria. And in Dermato- 
carpon at least the paraphyses gelatinize with age, reminding one again of Verrucaria. 
The present family is closely related to the next as shown in the very similar apo- 
thecial development in both Endocarpon and Dermatocarpon, the amphithecium 
partly or wholly replacing the usually stronger perithecium. 
Thelocarpon is certainly aberrant and is placed here provisionally. 
THELOCARPON®: Nyl. Mém. Soc. Sci. Nat. Cherb. 2: 15, 338, 1854. 
The thallus is crustose and verrucose, sometimes spread over the substratum as a 
thin, continuous or broken layer, but oftener entirely disappearing except the hemi- 
spherical nodular veil covering the apothecia. There is no suggestion of any ditfer- 
entiation into layers, and the algal symbiont is a form of Cystococcus or Pleurococcus. 
In color the thallus varies from whitish to greenish, 
The apothecia resemble those of Endocarpon and Dermatocarpon in that they are 
inclosed in the rudimentary exciple (perithecium), except for the pore or ostiole, and 
in that the amphithecium is present. Also there is a resemblance in that the apo- 
thecia are immersed in the thallus, which is often reduced to the thalloid veil sur- 
rounding them. The whole inner apothecium, including spores, paraphyses, asci, and 
amphithecium, is pale. Nylander includes in his genus forms having 8 spores in 
each ascus and also others having polysporous asci,¢? though he originally described 
the genus as polysporous. The spores are simple and hyaline, or in some species 
partly 2-celled. 
The relationship of the genus is by no means plain and we can perhaps do no better 
than to allow it to remain where its author placed it, near Dermatocarpon. 
A single species has been found in the State. On old pine boards and posts and 
rarely on rocks. 
Type species Thelocarpon albidum Nyl. loc. cit. 
aNyl. Mém. Soe. Acad. Maine et Loire 4: 60. 1858. 
b Tuck. Gen. Lich. 272. 1872. 
¢ The original spelling is followed here and in the next genus. 
dNyl. Mém. Soc. Acad. Maine et Loire 4: 9. 1858. 
