42 Minnesota Algae 



green, rarely violet, rose-pink or red; reproduction by division of the cells 

 in two directions. 



I Cells 5-7 mic. in diameter, 6-9 mic. in length. 



1 Colonies 30 mic. in diameter; cells 5 mic. in diameter, somewhat 



spherical; cell contents blue-green or violet. M. aerugineum 



2 Cells spherical or oblong M. elegans 



3 Cells oval M. novum 



II Cells 3-6 mic. in diameter. 



1 Colonies 45-150 mic. m diameter; cells spherical or oval 



M. glaucum 



2 Colonies large, more or less convolute; cells spherical or oblong 



M. convolutum 



III Cells 1.3-2 mic. in diameter, somewhat spherical M. tenuissimum 



97. Merismopedium aerugineum Brebisson in Kuetzing. Spec. Algar. 472. 



1849; Tab. Phyc. 5: 13. pi. 38. f. 8. 1855. De Toni. Syll. Algar. 5: 107. 

 1907. 

 Richter. Siisswasseralgen aus dem Umanakdistrikt. Bib. Hot. Heft. 42. 

 3- 1897. 



Plate II. fig. 32. 



Plant mass somewhat limited, nearly colorless; colonies 30 mic. in 

 diameter, 35-68 mic. in length, composed of from 4 to 64 cells; cells 5 mic. 

 in diameter, somewhat spherical, crowded; cell contents blue-green. 



Greenland. Umanak. (Vanhoffen). 



Var. violaceum Rabenhorst. Die Algen Sachsens. no. 857. 1859. De 

 Toni. Syll. Algar. 5: 107. 1907. 



Saunders. Protophyta-Phycophyta. Flora of Nebraska. 17. 1894. Til- 

 den. List of Fresh-Water Algae collected in Minnesota during 1893. Minn. 

 Bot. Studies. 1: 31. 1894. 



Cells very much crowded; cell contents violet. 



Wisconsin. Trout-mere. Osceola. October 1893. (MacMillan.) Ne- 

 braska. Quite common in stagnant ponds about Thedford, forming violet 

 or purplish slimy masses sometimes reaching the size of one's hand. (Saun- 

 ders). 



98. Merismopedium elegans A. Braun in Kuetzing. Spec. Algar. 472. 1849. 



De Toni. Syll. Algar. 5: 104. 1907. 



Snow. The Plankton Algae of Lake Erie. U. S. Fish Comm. Bull, for 

 1902. 22: 392. 1903. Buchanan. Notes on the Algae of Iowa. Proc. Iowa 

 Acad. Sci. 14: 9. 1908. 



Plate II. fig. 33. 



Colonies at first mucous, more or less limited, colorless, later be- 

 coming membranaceous, expanded, containing from 64 to 1856 cells, green- 

 ish; families quadrate, finally not distinctly limited; cells 5-7 mic. in diame- 

 ter, 6-9 4lic. in length, spherical or oblong; cell contents pale blue-green. 



