34 Minnesota Algae 



spherical, distinctly limited; cells somewhat spherical or ellipsoid 

 (size unknown) M. piscinalis 



S Colonies irregular in shape, with an indistinctly limited tegument; 

 cells 5-5.5 mic. in diameter, spherical or oval 



M. pallida 



80. Microcystis ichthyoblabe Kuetzing. Tab. Phyc. i: 7. pi. 8. 1845-1849. 



De Toni. Syll. Algar. 5: 88. 1907. 



Wolle. Fresh-Water Algae U. S. 330. 1887. Wolle and Martindale. 

 Algae. Britton's Catalogue of Plants found in New Jersey. Geol. Surv. N. J.. 

 2: 611. 1889. Snow. The Plankton Algae of Lake Erie. U. S. Fish Comm. 

 Bull, for 1902. 22: 392. 1903. (Polycystis icthioblabe Kg.) 



Colonies membranaceous, thin, more or less spherical, surrounded by a 

 common gelatinous tegument, usually containing several daughter colonies 

 each surrounded by its own tegument, blue-green; cells 2-4 mic. in diameter, 

 spherical; cell contents showing vacuoles, pale blue-green. 



United States. (Pike, Farlow, Collins). New Jersey. Occasional 



in small pools. (Wolle). Ohio. Put-in-Bay. Lake Erie. (Snow). 



81. Microcystis donnellir Wolle. Fresh Water Algae. Bull. Torr. Bot. Club. 



6: 282. 1879. 



Plant mass dull yellowish becoming olive; colonies 30-70 mic. in diam- 

 eter, spherical or oval, often more or less angular, green; cells 2.2-4 mic. 

 in diameter; cell contents granular, green. 



Maryland. In soft gelatinous masses, often nine and ten inches in 

 diameter, floating in ponds, Garrett County. July 1878. (Smith). 



82. Microcystis marginata (Meneghini) Kuetzing. Tab. Phyc. i : 6. pi. 8. 



1845-1849. De Toni. Syll. Algar. 5: 91. 1907. 

 Wolle. Fresh Water Algae. IL Bull. Torr. Bot. Club. 6: 137. 1877. 

 (Anacystis marginata Menegh.); Fresh-Water Algae U. S. 329. 

 1887. (A. marginata Kg.) Fanning. Observations on the Algae 



of the St. Paul city water. Minn. Bot. Studies. 2: 613. pi. 45. 1901. Saun- 

 ders. The Algae. Harriman Alaska Expedition. Proc. Wash. Acad. Sci. 

 3: 397. 190I. (M. marginata Naeg.) Setchell and Gardner. Algae 

 of Northwestern America. Univ. Calif. Pub. Bot. 1: 180. 1903. Clark. 

 The Holophytic Plankton of Lakes Atitlan and Amatitlan, Guatemala. 

 Proc. Biol. Soc. Wash. 21: 94. 1908. 



Plate IL fig. 17. 



Colonies spherical, flattened or orbicular and lens-shaped, sometimes 

 confluent, surrounded by a thick, lamellose common tegument, pale green, 

 colorless at the margin; cells 3-4 mic. in diameter, densely crowded, spher- 

 ical or sometimes angular; cell contents blue-green, becoming granular. 



United States. In ponds of stagnant water. (Wolle). Alaska. Form- 

 ing a slimy coating on a perpendicular cliff. Near Juneau. (Saunders); form- 

 ing slimy coatings on dripping rocks. Glacier Valley, Unalaska. (Setchell 

 and Lawson). Minnesota. St. Paul city water. (Fanning). Central 

 America. Lake Amatitlan, Guatemala. (Meek). 



