238 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Includes also the plants reported in the preliminary reports as Pyrenula hyalospora, 
spore characters agreeing with those of the present species. 
Collected at Granite Falls, Mankato, and Red Lake. On trees. 
Elsewhere in North America in Pennsylvania, South Carolina, Florida, and Iowa 
Known also in Asia. 
Pyrenula quinquese ptata of the preliminary reports. 
5. Arthopyrenia punctiformis (Pers.) Mass. Ric. Lich. 168. f. 335. 1852. 
Verrucaria punctiformis Pers. Ann, Bot. Usteri 11: 19. 1794. 
Thallus hypophloeodal and indicated at the surface by a slight change in color of 
the substratum, usually to lighter color, but frequently disappearing; apothecia also for 
most part hypophleeodal, depressed, rounded or oblong, minute or small, 0.1 to 0.9 
mm. broad (the latter the long dimension in oblong forms), the perithecium well 
developed in the upper portion, there dark brown, the amphithecium pale; paraphyses 
slender, distinct and commonly simple; asci cylindrical or cylindrico-clavate; spores 
oblong-ellipsoid, 2 to 4-celled, 18 to 24 » long and 5 to 7 » wide. 
Generally distributed in the State. On trees. 
Elsewhere in North America in New England, the Southern States, Illinois, Iowa, 
Nebraska, Missouri, and California. Known also in Europe, Asia, Africa, and New 
Zealand. 
Pyrenula punctiformis of the preliminary reports. 
5a. Arthopyrenia punctiformis fallax (Nyl.) Fink. 
Verrucaria epidermidis fallax Nyl. Mém. Soc. Acad. Maine et Loire 4: 59, 1858. 
Differs in that the paraphyses are scarcely so distinct and the spores frequently 
become obscurely muriform; apothecia rather smaller and more superficial. 
Throughout the northern portion of the State. Commonly on birches. 
Elsewhere in North America in Florida and California. 
The above is essentially Tuckerman’s disposition of the species and the subspecies. 
Perhaps all of the 4-celled forms should be referred to Arthopyrenia cerasi (Schrad.) 
Hepp, but this disposition has seemed scarcely better, 
Pyrenula punctiformis fallax of the preliminary reports. 
PYRENULA Ach. Lich. Univ. 64, 314. pl. 5. f. 1-5. 1810. 
The thallus is crustose and hypophloodal, or rarely in part epiphloodal, and it not 
infrequently disappears or becomes so nearly wanting that the best sections fail to 
bring out any evidence of either algal or fungal portions, above or within the sub- 
stratum. When the epiphloodal portion is present, it is very thin and smooth or 
faintly scurfy. In color the thallus is whitish, ashy, or slightly yellowish, and it is 
commonly widely and irregularly spread over the substratum, being recognizable 
merely as an area of somewhat different color. The algal sy mbiont is a form of 
Chroolepus. When the thallus is absent or only to be made out by the most careful 
microscopic examination the species are, like those of Arthopyrenia, frequently 
placed among certain closely related fungi, 
The apothecia are black in all of ours, more or less immersed in the substratum, and 
of the same general form, size, and structure as those of Arthopyrenia. The paraphyses 
differ from those of the Arthopyrenias in that they show less of the tendency toward 
gelatinized and coherent-indistinct conditions. The spores are brown, and the 
number of cells varies from 2 to several. They vary in form from oblong to ellipsoid. 
The relationship between the present genus and Verrucaria has been stated under 
the latter genus, and the difference in substratum plays no part in the separation of 
the two genera, except that it is doubtless largely responsible for the difference in 
structure, which is perhaps after all not sufficient to warrant the separation. 
Six species and subspecies occur in the State. On trees. 
