Tilden: list of fresh water algae. 27 



20. tticrospora fugacissima (Roth) Rab. F1. Eur. Algar. 



3 : 321. 1864-68. 

 Shadow falls, St. Paul. Sept. 6, 1893. 



21. Rhizoclonium hieroglypliicum (Ag.) Kg. Phyc. Gener. 



205. 1843. 

 Taylor's Falls. Sept. 16, 1893. 



VAUCHERIACEAE (Gray) Dumort. Comm. Bot. 71. 1822. 



22. Vaucheria ornithocephala Ag. Spec. 467. 1821-1828. 



Shadow falls, St. Paul, Sept. 6, 1893. 



23. Yaucheria hamata (Vauch.) DC. Fl. Fr. 2 : 63. 1815. 



Stone quarry, Minneapolis. Sept. 13, 1893. 



24. Vaucheria gemiiiata (Vauch. ) DC. Fl. Fr. 2 : 62. 1815. 



Taylor's Falls. Sept. 16, 1893. 



VOLTOCACEAE (Cohn) Kirchn. Alg. Schles. 85. 1878. 



25. Yolvox globator (Linn.) Ehrenb. Infus. 68. 1838. 



Pool near lake Kilpatrick. July 7, 1893. 



PALMELLACEAE (Decne.) Naeg. em. De Toni, Syll. Alg. 

 1 : 559. 1889. 



26. Pediastrum boryanum (Turpin) Menegh. Linnaea. 



1 4 : 210. 1840. 

 Mud lake. June 29, 1893. 



27. Hydrodictyon reticulatum (Linn.) Lagerh. Bidr. 



Svrg. Algfl. n. 2. 71. 1883. 

 Minneapolis. Oct. 25, 1893. 



28. Scenedesmiis quadricaiida (Turpin) Breb. Alg. Falais. 



66. 1835. 

 Marsh near Stony brook. July 11, 1893. 

 Minneapolis. October 5, 1893. 



29. Ophiocytium ? capitatum Wolle, Preshw. U. S. 176. 



1887. 

 Monroe. July 12, 1893. 



30. Reinschiella ? cuspidata (Bailey) De Toni, Syll. Alg. 



1 : 614. 1889. 

 Peat-bog near lake Kilx)atrick. July 13, 1893. 



31. Characium ambiguiim Herm. Rabenh. Beitr. 26 n. 10. 



1862-65. 

 Marsh near Gull lake. June 28, 1893. 



