[Vol. 10 



388 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



free water close to shore, while in other parts the shores may be 

 gently sloping, with sandy or muddy bottom, and largely over- 

 grown with rushes, sedges, and pond-weeds of various sorts. The 

 alkaline lakes in general lack the abundant growths of these 

 plants, but their place is largely taken by Ruppia and the bottom 

 is more apt to be covered by fine black ooze, the result of accu- 

 mulation of large amounts of wind-borne dust and decaying 

 plant and animal life. Both phyto- and zoo-plankton are gener- 

 ally abundant in all of the lakes, especially the former, which 

 frequently forms a "water-bloom" on the surface. 



The lakes may be grouped roughly into (1) freshwater, those 

 with total alkalinities below 400 ppm., (2) intermediate, with 

 alkalinities between 400 and 700 ppm., and (3) alkaline lakes 

 with alkalinities above 700. 



(1) Freshwater lakes. Here may be included those in the 

 Turtle Mountains (Carpenter, Crow, Dion, Fish, Gravel, Gordon, 

 Jarves, Metigosche, and Willow), and those in the James River 

 Valley (Arrowhead and Jim Lakes), Court, Crooked, Ensign, 

 near Frettem, Fort Totten, Juanita, Long Lake, near Ruso, 

 Painted Woods, Red Willow, near Binford, Spiritwood I and II, 

 Strawberry, South Twin (Lake Y) and Wood Lakes, besides a 

 few others, which are mere ponds formed by the outflow of springs 

 (Cut-off, Eastgate's, and W'heeler's Ponds I and II, near Stump 

 Lake, and ponds H and I at the Odessa Narrows). 



(2) Intermediate Lakes. Blue, Brush, Clear, Florence, Long 

 Lake, near Binford, Sweetwater, South Free Peoples, Williams, 

 and X. 



(3) Alkaline lakes are those of the Devils-Stump Lake complex, 

 including Main, East, Lamoreau, Stump, Mission, and Spring 

 Lakes, and Lakes A, C, N 1 , O 1 and P, besides Alkaline Lakes I 

 and II, Buffalo, Coe, Etta, Four-Mile, North Free Peoples, 

 Isabelle, Tokio, Twin, North and South Washington Lakes, 

 I,ake Z, and the ponds south and southwest of Brush Lake. 



For most of the lakes only alkalinities have been determined. 

 Of several, however, general analyses have been made. Three of 



1 These are temporary pools formed b 

 Bions in the floor of the old Devils Lake, 

 to time. 



time 



