CLASSIFIED CATALOG OF ILLINOIS ALGAE 95 



O. PLAGiosTOMUM Wittr. Tiffany, loc. cit., p. 36. pi. 11. f. 141, 142 



(1937). 



Transeau 1913B, p. 84: Coles, Charleston — ponds (Oct.). Tiffany 

 1930, p. 80; 1937, p. 36; 1939, p. 91. 



O. PLUSIOSPORUM Wittr. Tiffany, loc. cit., p. 30. pi. 8. f. 97, 98 (1937). 

 Transeau: Coles, Ashmore — ^ponds (Apr.). 



O. PRATENSE Trans. Tiffany, loc. cit., p. 49. pi. 21. f. 325, 326 (1937). 

 Transeau 1914, p. 297; Collins 1918, p. 66: Clark, Casey— pond 

 (July). Coles, Charleston, Lerna — ponds and pools (Mar.-May, 

 Nov.). Britton: Cook, Northbrook — small pond at Somme For- 

 est Preserve, May 15, 1938, #68. Tiffany 1930, p. 102; 1937, 

 p. 49; 1939, p. 91. 



O. PRATICOLUM Trans. Tiffany, loc. cit., p. 81. pi. 29. f. 461-463 (1937). 

 Transeau 1914, p. 298; 1916, p. 124; Collins 1918, p. 68: Clark, 

 Casey — ponds (July). Coles, Charleston — ponds (June-Nov.). 

 Tiffany 1930, p. 156; 1937, p. 81; 1939, p. 91. 



O. PRiNGSHEiMii Cram. Tiffany, loc. cit., p. 50. pi. 21. f. 312, 313 



(1937). 



Transeau: Coles, Charleston — pond and pool (May, June, Oct.). 



O. PRINGSHEIMII var. NORDSTEDTii (Wittr.) Wittr. Tiffany, loc. cit., f. 



314-317 (1937). 



Transeau 1913B, p. 85: Clark, Casey— pond (Nov.). Coles, 

 Charleston — ponds, pools and small streams (May, July, Oct.). 

 Douglas, Arthur— pond (Aug.). Tiffany 1930, p. 108; 1937, p. 50. 



O. PSEUDO-Boscii Hirn. Tiffany, loc. cit., p. Z^. pi. 10. f. 130 (1937). 

 Transeau 1913B, p. 85: Coles, Charleston — prairie ponds and 

 pools (Apr., May). Tiffany 1930, p. 76; 1937, p. ZZ; 1939, p. 91. 



O. PUNCTATOSTRIATUM DeBary. Tiffany, loc. cit., p. 27. pi. 23. f. 364, 



365 (1937). 



Transeau: Coles, Charleston— lake (Aug.). Tiffany 1930, p. 104; 

 1937, p. 29; 1939, p. 91. 



O. PUNCTATUM Wittr. Tiffany, loc. cit., p. 44. pi. 17. f. 244, 245 (1937). 

 Transeau: Clark, Casey — pond (Oct.). Jasper, Wheeler — pond 

 (Aug.). 



O. PUNGENS Hirn. Tiffany, loc. cit., p. 57. pi. 30. f. 483, 484 (1937). 

 Transeau 1913B, p. 85: Coles, Charleston, Lerna — ponds (May). 

 Tiffany 1930, p. 122; 1937, p. 57; 1939, p. 91. 



O. PUSILLUM Kirch. Tiffany, loc. cit., p. 82. pi. 19. f. 287 (1937). 

 Collins 1912, p. 88; Transeau 1913B, p. 85: Coles, Charleston- 

 ponds (May-July). Cumberland, Greenup — 5 miles N. in Em- 

 barrass River (Sept.). Tiffany 1930, p. 161; 1937, p. 82; 1939, 

 p. 91. 



O. RivULARE A. Br. Tiffany, loc. cit., p. 37. pi. 11. f. 139, 140 (1937). 

 Transeau: Coles, Ashmore — pond (Apr.). 



