696 MINNESOTA BOTANICAL STUDIES. 
104. Pertusaria pustulata (Acu.) Nyt. 
On trees, infrequent. Battle lake, June 22, 1900, no. 129. 
Henning, June 29, 1900, no. 361 and June 30, 1900, no. 383. 
Bemidji, July 13, 1900, nos. 707 and 719. 
105. Pertusaria finkii A. ZAHLB. in litt. 
On trees, rare or infrequent. Battle lake, June 20, 1g00, 
ho: 74, June 21,'7900, no. 113, and June 26, 1900; non maee 
Henning, June 30, 1900, no. 366. Bemidji, July 5, 1900, no. 
480. Thief River Falls, July 18, 1900, no. 801. Red lake, 
July 31, 1900, nos. 1014 and 101g. 
Thallus white or whitish, thin (0.2-0.28 mm.), determinate or 
subdeterminate, margin continuous, center unequal-verrucose 
and rimose, ecorticate, medullary hyphz slender, algal cells 
globose, green, 10-15 mic. in diameter, disposed in more or less 
discrete clusters. Apothecia plentiful, clustered, immersed or 
finally becoming open-lecanoroid, about 0.75 mm. in diameter, 
irregular.or subrotund, fuscescent or blackish, flat, rough; 
thalline margin persistent, thin, whitish, crenulate to sublacerate. 
Hymenium 320-370 mic. deep. Epithecium rufescent or fus- 
cescent. Paraphyses slender, somewhat conglutinate. Asci 
elevate-saccate, containing 2 (rarely 1) spores, straight or some- 
what curved, apex rounded and thickened, 170-190 mic. long 
and 42-46 mic. wide. Spores oval, ellipsoid or oblong, occa- 
sionally somewhat constricted along the sides, simple, colorless, 
88-140 mic. long and 28-53 mic. wide, spore walls thick (g— 
r2.imic:)). 
106. Urceolaria scruposa (L.) Nyt. 
On calcareous earth, rare. Battle lake, June 20, 1900, nos. 
52 and 96. Leaf hills, June 27, 1900, no. 255. 
107. Stereocaulon paschale (L.) Fr. 
On granitic bowlders, rare. Bemidji, July 10, 1900, no. 
569 and July 16, 1900, no. 750. Red lake, August 4, 1900, 
nos. 1079 and 1082. 
108. Cladonia mitrula Tuck. 
On earth, rare. Battle lake, June 20, 1900, no. 53. Hen- 
ning, June 28, 1900, no. 308. Leaf hills, July 2, 1900, no. 402. 
10g. Cladonia botrytes (Hac.) WILLD. 
On coniferous stumps and logs, infrequent. Bemidji, July 
4, 1900, no. 430 and July 6, 1900, no. 526. Thief River 
Falls, July 17, 1900, no. 771. Red lake, July 28, 1900, no. 
974- 
