Whereas a few reports have been published on freshwater algae of eastern Arctic America (e.g., Cedercreutz, 1944; Dickie, 1880; Dutilly & Lepage, 1946; Gardner, 1949; Jennings, 1936; Lowe, 1923; Whelden, 1947) we have practically no knowledge of the flora in northern Alaska. Saunders (1901) has made a helpful contribution to a knowledge of Alaskan algae, but his teport is based on collections b'elow the Arctic Circle. Most of our information on these plants in the Arctic has come from the surveys made in Greenland, Lapland, and northern Russia (e.g., Boergesen, 1896, 1901, 19'17; Bohlin, 1893; Boldt, 1885, 1893; Borge, 1891, 1892, 1894; Gr6nblad, 1924; Kossinskaja, 1936; Krieger, 1938; Lagerheim, 1883, 1884, 1884-a, 1894, 1900; Larsen, 1907; Nordstedt, 1872, 1875, 1885; Voronikhin, 1930; Wille, 1879, 1880; Wittrock, 1872, 1883, and many others). A survey of western Arctic algae is highly desirable, therefore, from both a taxonomic and an ecological point of view. We need to determine the circumpolar distribution of species and also to determine the extent to which temperate zone algae are distributed in the Arctic. The Arctic slope in northern Alaska is a supposedly unglaciated, nearly flat tundra, sloping gently from the Brooks Range to the Arctic Ocean, lying within 67?-710 21' N. Lat. Throughout this plain are innumerable lakes, the larger ones of which are curiously oriented northwest-southeast. The lakes vary in size from ponds a few acres in area to bodies of water 5 to 20 miles or more in length. Between the lakes occur hundreds of thousands of small ponds and swales, and between these are pools, seeps, and ditches so that in many sections there is more water than land surface (710-710 10' N. Lat., 1560 20'-1560 40' W. Long., e.g.). Environmental conditions would seem to be somewhat uniform throughout much of this monotonous expanse, and whereas a correspondinlg similarity might be expected to exist in the algal flora of the lakes, such has not been found to be thc case. The Arctic Research Laboratory with its facilities for both outdoor and indoor operations is being used as a base for a survey of the algal flora of the Arctic slope. In following out the taxonomic objectives of this investigation analyses are being made of the pertinent limnological factors to determine what correlated conditions exist which might explain the variability in the flora of closely situated lakes. A year-around investigation