2 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
or 
2. Acolium lucidum (Th. Ir.) Fink. — 
Trachylia lucida Th. Fr. Ofv. Vet. Akad. Férh. 12: 18. 1855, 
Thallus crustose, verrucose, scarcely reaching an areolate condition, the verruc:e 
usually more or less scattered upon the substratum, but sometimes forming a con- 
tinuous crust over small areas of the substratum, lemon-yellow or yellowish green; 
apothecia of about the same size as those of the last, but on somewhat longer stipes, 
so that the apothecium appears to be sessile upon the thallus or rarely elevated suffi- 
ciently so that the stipe way be seen without sectioning, the disk flat and at first 
bluish green pruinose, the exciple black and prominent: hypothecium dark brown; 
hymenium pale and frequently brownish above; paraphyses coherent and indistinct 
in ours examined; asci cylindrical or irregularly cylindrico-clavate; spores brown, 
2-celled, ellipsoid, 6 to 9 # long and 3 to 4 « wide. 
In northern Minnesota. On pines and other conifers and on dead wood. 
Not known elsewhere in North America. Also in Europe. 
Calicium lucidum of the preliminary reports. 
Family GRAPHIDACEAE. 
The characters by which the Graphidaceae may most readily be distinguished 
are those of the apothecia. These organs are commonly elongated or irregular and 
often branched. Yet a few somewhat rounded apothecia are occasionally seen in 
some of the species. These remind one of those of Melaspilea, but in ours at least 
the spore characters will always serve to distinguish very easily. Likewise, the 
clustered apothecia of Gyrophora remind ene externally of those of some members 
of the present family, but sections of the apothecia of the Gyrophoras reveal a higher 
type of structure, and the differences in thalli in the Graphidaceae and the Gyro- 
phoraceae are easily observable. 
The thallus is crustose and usually hypophleeodal in our species, though some 
species not found in our flora occur on rocks. The structure of the thallus is quite 
rudimentary, as there is seldom any sign of differentiation, The algal symbiont is 
Chroolepus. The thallus characters are substantially the same as in the Pyrenula- 
ceae, but in that family we have the spheroidal apothecia provided with a well- 
developed perithecium, by which difference the two families are to be distinguished, 
The spore characters are sufficiently explained in the outline of the families. 
It is not at all probable that the genera of the family all had a common origin, and 
yet both the apothecial and the thallus characters would seem to indicate a close 
relationship. 
The family is mainly southern in distribution, and the number of genera and species 
found in Minnesota is not large. The plants usually occur on smooth bark. Craphos 
scripta is by far the most common member of the family in Minnesots. 
OPEGRAPHA Humb. FI. Friberg. 57. 1793. 
The thallus is crustose and mainly hypophloeodal, forming a smooth crust upon 
the substratum when the epiphlceodal portion of the thallus is not entirely wanting, 
devoid of differentiation into layers, and, as usual in such low lichens, the hyphal 
Thizoids extending some distance into the substratum, The algal symbiont is a 
form of Chroolepus. 
The apothecia are linear, oblong, or more or less rounded or irregular, rarely 
branched, with a usually narrowly furrowed or concave disk, superficial or more or 
less immersed in the substratum. The proper exciple is black, heavy, and promi- 
nent. The spores are 4 or more celled, and fusiform, ellipsoid, or finger-shaped, 
though some lichenists include in the genus similar lichens having persistently 
2-celled spores, 
