164 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Generally distributed over the State. On earth and old wood. 
The North American distribution seems to be about the same as that of the species. 
Also known in Europe and Asia. 
8c. Peltigera canina sorediata (Schaer.) Fink, Bull. Lab. Nat. Hist. Univ. lowa 
3: 76. 1895. 
Peltigera canina spuria sorediata Schaer. Enum. Lich. Eur. 21. 1850, 
Thallus small, composed of usually scattered lobes, these sorediate and 10 to 45 mm. 
in length, the ends usually rounded and sterile; beneath either bearing rhizoids or 
not; apothecia rather smaller than in the species, not differing microscopically. 
Found in all portions of the State. On earth or old logs in moist shaded places, 
North American distribution the same as that of the last, into which it frequently 
passes. Known also in Europe. 
8d. Peltigera canina leucorrhiza Floerke, Deutsch. Lich. no, 53. 1821. 
Thallus rather expanded and thinner, the conspicuous veins and scattered rhizoids 
white. The largest form of the species, reaching 27.5 cm. in diameter, or the large 
rounded lobes scattered. Usually sterile; trichomatic hyphe abundant and large; 
apothecia not seen, 
Found in the northern portion of the State. On earth or over mosses in swamps. 
Agrees with material determined from Newfoundland by Arnold. Nothing further 
known of its American distribution. Known in Europe. 
NEPHROMA Ach. Lich. Univ. 101, 521. pl. 77. f. 1. 1810. 
The thallus is foliose and bears a general external resemblance to that of Peltigera, 
though smaller, usually darker in color and devoid of trichomatic hyphe. It lies 
horizontally on the substratum, to which it is usually more or less closely attached 
by rhizoids. The cortical layer is developed on both sides, the upper cortex being 
much thicker than the lower. The algal and medullary layers are well developed. 
There is some uncertainty regarding the algal symbiont, and Nylander has divided 
the genus, establishing the genus Nephromium, the distinction being based upon the 
difference in the alge. All of our species would fall under his newer genus were 
we to follow his distinction. However, we have retained the older name, awaiting 
further studies. The algze in ours are blue-green, and seem to be the same as in 
Peltigera, viz, Polycoccus. 
The apothecia are confined to the lower side of the thallus, and this feature serves 
to distinguish the members of the genus from members of closely related genera as 
Peltigera and Solorina. However, the apothecia are marginal or submarginal, and 
the disk is more or less turned upward and may even stand erect. They are of good 
size, somewhat impressed in the more or less elongated lobes which bear them. The 
algal cells commonly disappear from the thalloid margin, which may itself be eva- 
nescent. The hypothecium is pale or brownish. The paraphyses are commonly 
simple with apices enlarged and brownish. The spores are brown or brownish, and 
commonly 4-celled in ours. 
The genus is certainly closely related to Peltigera as to apothecial characters and 
also as regards general appearance of the thallus. As regards microscopic features 
of the thallus and the spores, it seems nearer to Sticta. 
Four species and subspecies have been found in the northern portion of the State, 
a single species extending as far south as Taylors Falls. 
The plants occur on trees, rocks, and occasionally on soil, and are quite commonly 
found on mosses overrunning these substrata. 
Type species Nephroma polaris Ach. loc. cit. (Nephroma aretica (1..) Fr.) 
