WISCONSIN PHYTOPLANETON 137 



SCHROEDERIA SETiGERA (Schroder) Lemmermann. PI. 32, Fig. 12. 



Hedwigia 37: 311. 1898; G. M. Smith, Bull. Torr. Bot. Cl. 43: 473, pi. 24, 



fig. 8. 1916. 



Length of cells 15-20 times breadth. (Euplanktont). 

 Cells 3-6 /t broad, 60-85 p. long (with spines). Length of spines 

 13-27 p.. 



Chain (sss), Devils (1) (c), Long (2) (rr), Sand (1) (rr). 



This peculiar alga has the general appearance of a Characium. Al- 

 though hundreds of individuals have been found, it has never been 

 found attached to other algae or to crustaceans so that it seems safe 

 to assume that it leads a free-floating and not an epiphytic existence. 

 The disc at one end of the setae described above has not been observed 

 by other investigators, possibly because the alga is very minute. 



Reproductive stages have never been found so that the systematic 

 position of the genus is doubtful. Judging by the cell shape it is a 

 close relative of Ankistrodesmus, a genus to which it has been referred 

 by some. 



SCHROEDERIA JUDAYI G. M. Smith. PI. 32, Figs. 9-11. 



Bull. Torr. Bot. Cl. 43: 474, pi. 24, figs. 9-11. 1916. 



Cells smaller than the foregoing. (Euplanktont). 

 Cells 2.5-6 p broad, 45-63 /* long (with spines). Length of spines 

 10-16 ft. 



Amicoy (rr), Birch (rrr), Camp (rr), Delavan (rr), Kawaguesaga (rr), 

 Mendota (sss), Prairie (rr), Round (1) (rrr), St. Croix (rr). 



QUADKIGULA Printz 1915. 



Cells generally in groups of 2-4-8 with their long axes parallel to 

 the long axis of the colony and enclosed by a hyaline, homogeneous, 

 gelatinous sheath. Colonies ellipsoid, 2-5 times as long as broad. Cells 

 cylindrical to fusiform, 4-7 times as long as broad, straight or slightly 

 curved. Chloroplast single, filling most of the cell; with or without 

 pyrenoids. 



Reproduction by 2-4-8 autospores from each cell, the fasiculate group 

 of autospores frequently remaining within the envelope of the mother 

 colony for some time. 



