690 MINNESOTA BOTANICAL STUDIES. 



56. Collema ryssoleum TUCK. 



On Popttht3 t rare. Bemidji, July 12, 1900, no. 686. 

 Not previously reported from Minnesota. 



57. Collema pulposum (BERNH.) NYL. 



On earth, rare. Battle lake, June 20, 1900, no. 77. Leaf 

 hills, June 26, 1900, no. 207. Henning, June 29, 1900, no. 

 352. Leaf hills, July 2, 1900, no. 400. Bemidji, July 5, 

 1900, no. 477. Thief River Falls, July 17, 1900, nos. 769 and 

 770. 



58. Collema crispum BORR. 



On earth, frequent. Bemidji, July n, 1900, no. 605. 



59. Collema limosum ACH. 



On earth, infrequent. Bemidji, July 10, 1900, no. 568, 

 July n, 1900, no. 637 and July 14, 1900, no. 736. 

 Not previously reported from Minnesota. 



60. Leptogium lacerum (Sw.) FR. 



On earth, rare. Leaf hills, June 27, 1900, no. 287. Thief 

 River Falls, July 18, 1900, no. 795. 



61. Leptogium myochroum (EHRH., SCHAER.) TUCK. 



On trees and rocks, rare. Battle lake, June 21, 1900, no. 

 123 and June 23, 1900, no. 156. Henning, June 30, 1900, nos. 

 381 and 382. Bemidji, July 5, 1900, no. 485 and July 13, 

 1900, no. 710. 



62. Placodium elegans (LINK.) DC. 



On granite and limestone, rare. Battle lake, June 20, 1900, 

 nos. 60 and 66. Bemidji, July n, 1900, no. 638. Thief River 

 Falls, July 17, 1900, no. 776. 



63. Placodium murorum (HOFFM.) DC. 



On lime bowlders, rare. Thief River Falls, July 9, 1900, 

 no. 825. With deficient thallus. 



64. Placodium cinnabarrinum (Acn.) ANZ. 



On granite rocks, infrequent. Battle lake, June 20, 1900, 

 nos. 45 and 50. Leaf hills, June 27, 1900, nos. 276 and 282. 



65. Placodium aurantiacum (LIGHTF.) NAEG. and HEPP. 



On trees and granites, infrequent. Battle lake, June 19, 

 1900, no. 37. Leaf hills, June 27, 1900, no. 253. Bemidji, 

 July n, 1900, no. 643. Thief River Falls, July 19, 1900, no. 



