316 MINNESOTA BOTANICAL STUDIES. 



70. Placodium citrinum (Hoffm.) Leight. 



On limestone, rare. Mankato, June 26, 1899, no. 117. 



71. Placodium cerinum (Hedw.) Naeg. and Hepp, 



On trees and old wood, common. Mankato, June 22, 1899,. 

 no. 18, and June 23, 1899, no. 75. Mankato (Rapidan), June 

 28, 1899, nos. 178 and 179. Granite Falls, July 11, 1899, ^^^* 

 432 and 435. Granite Falls, July 17, 1899, no. 553. 



72. Placodium cerinum (Hedw.) Naeg. and Hepp. var. sider- 

 itis Tuck. 



On granitic rocks and catlinite, common. Mankato, June 

 23, 1899, ^'^- 4^' J"^"^ -^' 1899, no. 114, and June 30, 1899, 

 no. 198. New Ulm, July 5, 1899, no. 247. Granite Falls, 

 July 12, 1899, no. 444. Pipestone, July 18, 1899, no. 613. 



73. Placodium cerinum (Hedw.) Naeg. and Hepp. var. pyracea 

 Nyl. 



On old boards, infrequent. Mankato, June 22, 1899, no. 2. 

 Granite Falls, July 11, 1899, no. 430. 



74. Placodium ferrugineum (Huds.) Hepp. 



On old wood, rare. Mankato, June 22, 1899, no. 17. 

 Not previously reported from Minnesota. 



75. Placodium ferrugineum (Huds.) Hepp. var. poUinii Tuck. 

 On dead cedars, rare. New Ulm, July 4, 1899, no. 230. 

 Not previously reported from Minnesota. 



76. Placodium vitellinum (Ehrh.) Naeg. and Hepp. 



On granite and quartzite, common. Mankato, June 30, 



1899, no. 203. New Ulm, July 5, 1899, no. 292. Granite 



Falls, July 12, 1899, no. 462. Pipestone, July 18, 1899, no. 

 629. 



77. Placodium vitellinum (Ehrh.) Naeg. and Hepp. var. aurel- 

 lum Acii. 



On granite, quartzite and sandstone, frequent. Mankato, 

 June 22, 1899, no. 10. New Ulm, July 4, 1899, nos. 233, 237 

 and 239. Granite Falls, July 14, 1899, no. 523. 



78. Lecanora sp. 



On granitic rocks, frequent locally. Granite Falls, July 11, 



1899, "°- 408. Spores -^ mic. Seems near Lecanora 



gelida (L.) Acli., but the thallus is probably too rough and 

 heavy. 



