WISCONSIN PHYTOPLANKTON 157 



SCENEDESMUS ABUNDANS (Kirchner) Chodat. PI. 39, Figs. 23-25. 



Mater, p. la fl. crypt. Sulsse. 4 2 : 77. 3913; G. M. Smith, Trans. Wis. Acad. Sci., 

 Arts, & Lett. 18 2 : 465, pi. 31, figs. 137-140. 1916. 



Scenedesmus quadricauda var. abundans (Kirchner) Lagerheim, ofvers. 

 Kgl. Vet.-Ak. Forh. 39, No. 2: 64, pi. 2, fig. 20. 1882. 



Coenobe flat, generally 4-celled. Cells ovoid to oblong-ellipsoid. 

 Terminal cells with 1-2 spines at poles and additional spines on outer 

 face between the poles. Interior cells with 1-2 spines at each pole. 

 (Facultative Planktont). 



Cells 4-7 p. broad, 7-12 p. long. 4-celled coenobia 7-12 p. broad, 

 15-30 fi long. Spines 4-7.5 p, long. 



Beaver (2) (rr), Cbchrane (rr), Diamond (rr), Grassy (rr), Horse (rr), 

 Long (1) (rrr), Nancy (rrr), Palmer (rr), Poor Farm (ss). 



var. LONGICAUDA G. M. Smith. PI. 39, Figs. 26-27. 

 Trans. Wis. Acad. Sci., Arts, & Lett. 18 2 : 467, pi. 30, figs. 121-125. 1916. 



Cells smaller, ovoid. Spines much longer in proportion to the size 

 of the cells. (Facultative Planktont). 



Cells 3-6 fjL broad, 7-9 p. long. 4-celled coenobia 7-9 p. broad, 10-15 

 p. long. Spines 6-10 p, long. 



Camp (rr), Chain (rrr), Horse (rr), White Ash (rr). 



var. BREVICAUDA G. M. Smith. PI. 40, Figs. 3-5. 

 Trans. Wis. Acad. Sci., Arts, & Lett. 18 2 : 468, pi. 30, figs. 126-132. 1916. 



Cells ovoid, smaller. Spines much shorter and never more than 

 three between the polar spines of terminal cells. (Facultative Plank- 

 tont). 



Cells 2.5-5 ju, broad, 5-8 p. long. 4-celled coenobia 5-8 p. broad, 

 10-13 /x long. Spines 1.5-3.5 //. long. 



Mendota (rr). 



var. ASYMMETRICA (Schroder) G. M. Smith. PI. 40, Figs. 6-8. 



Trans. Wis. Acad. Sci., Arts, & Lett. 18 2 : 468, pi. 27, figs. 45-46. 1916. 



Scenedesmus guadricauda var. asymmetrica Schroder, Forschungsbr. a. d. 

 Biol. Stat. zu Plon 5: 45, pi. 2, figs. 5a-5c. 1897. 



Coenobia generally 4-celled, with oblong-ellipsoid cells. Poles of 

 terminal cells with a single spine. All cells of coenobe with a single 

 median spine perpendicular to the plane of the coenobe and at one 

 side of cell only. (Facultative Planktont). 



Cells 2.5-4.5 p. broad, 12-15 //, long. 4-celled coenobia 12-15 p. bro 

 13-18 /i long. Spines 7-10 /u long. 



Blue Gill (rr), Wild Goose (rrr). 



