Oscillatoria sancta var. aequinoctialis Kuetzing 1845-1849, p. 30 

 A questionable variety, with a diameter in the upper hmits of the 

 species' range ( 14-20/x ) . 

 Mich. 



Oscillatoria splendida Greville 1824, p. 305 

 PI. 110, Figs. 5-7 

 Trichomes soHtary and scattered, rarely aggregated in small, 

 flake-like masses; straight or curved, tapering for a long distance 

 to a fine hair at the apex. Apical cell conical and capitate. Cells 

 2.2-2.8/1 in diameter, 7.2-9/i, long, not constricted at the cross walls; 

 cell contents finely granular or homogeneous, pale blue-green. 



Common in a variety of lakes with a high pH; generally distrib- 

 uted. Mich., Wis. 



Oscillatoria subbrevis Schmidle 1901b, p. 243 

 PI. 107, Fig. 23 

 Filaments solitary, not occurring in a plant mass; straight and not 

 tapering toward the apices. Apical cell rounded, not capitate and 

 without a calyptra. Cells short, 5-6/i, in diameter, 1-2/^ long, with 

 frequent necridia in evidence; cross walls not granular; cell contents 

 pale gray-green. 

 Mich. 



Oscillatoria tenuis C. A. Agardh 1813, Algarum Decades, p. 25 



PI. 110, Figs. 8, 9, 14 



Trichomes aggregated to form a blue-green mass, sometimes be- 

 coming scattered and appearing singly among other algae. Straight 

 or slightly flexuous, especially at the anterior end, which does not 

 taper; hormogonous sheath frequently present. Apical cell convex, 

 smooth, and not capitate; outer membrane sometimes slightly thick- 

 ened. Cells (4)-5-8-(10)/i in diameter, 2.5-3.2-(5)/. long; con- 

 stricted at the cross walls (sometimes only slightly so), which 

 are granular. 



Generally distributed and very common in tychoplankton of a 

 variety of lakes and ponds; in swamps and roadside ditches. Mich., 

 Wis. 



Oscillatoria tenuis var. natans Gomont 1892a, p. 221 

 PI. 110, Figs. 10, 11 

 A variety differing from the typical by having stouter trichomes 

 (in our specimens), which are 7.4-10/a in diameter; cells 3.4-4.6/x 

 long; apical cell truncately rounded. 



[491] 



