176 WISCONSIN PHYTOPLANKTON 



CHARACIUM STIPITATUM (Bachmann) Wille. PI. 49, Figs. 4-7. 



in Engler & Prantl, Nat. Pflanzenfam. I 3 (Nachtr.); 45. 1909; G. M. Smith, 

 Bull. Torr. Bot. Cl. 43: 472, pi. 24, flgs. 4-6. 1916. 



Cells spherical to pyriform, with a delicate hyaline stipe somewhat 

 longer than the cell. Chloroplast single, parietal, cup-shaped, always 

 on the side away from the stipe ; pyrenoid single. Zoospores broadly 

 ovoid, biciliate, with a cup-shaped chloroplast at the posterior end. 

 (Euplanktont). 



Epiphytic upon and embedded within the gelatinous envelope of 

 Coelosphaerium Naegelianum Unger. 



Cells 5-8 p. broad. Stipe 10-16 /u. long. 



Amicoy (r), Balsam (rr), Beartrap (rr), Beaverdam (s), Big (rr), Big 

 McKenzie (ss), Clam (ss), Devils (2) (ss), Horseshoe (1) (ss), Horseshoe 

 (2) (rr), Long (2) (ss), Kawaguesaga (ss), North Twin (sss), Pardee (r), 

 Pike (rr), Pokegama (1) (s), Pokegama (2) (r), Poplar (rrr), St. Croix (r), 

 Sand (4) (rr), Sishebogema (rr). 



In one case the alga was found upon Oocystis but in all others it was 

 inside the gelatinous envelope of Coelosphaerium Naegelianum Unger. 

 When the alga grows upon Coelosphaerium the colony is apt to be in- 

 fested with 50-100 individuals as a rule. The alga was originally des- 

 cribed as a Chlamydomonas species but since the sessile phase is the 

 dominant one of the life cycle it is better placed as a Characium species. 

 Although found at only one station in Europe it is widely distributed 

 in northern Wisconsin. 



CHARACIUM CURVATUM G. M. Smith. PI. 49, Figs. 8-15. 

 Trans.- Wis. Acad. Sci., Arts, & Lett. 19 1 : 641, pi. 11, figs. 6-13. 1918. 



Cells lunate or recurved, with acute or sub-acute apices. Stipe hya- 

 line, thick, tubular or conical, sometimes irregular in outline. Chloro- 

 plast single, parietal, laminate to cup-shaped ; with or without a pyre- 

 noid. ( Euplanktont) . 



Epiphytic upon Coelosphaerium Naegelianum Unger, Dictyosphaer- 

 ium pulchellum Wood, and Phaeococcus planctonicus W. & G. S. West. 



Cells 3-6 p. broad, 8-18 ^ long (without stipe), 13-22 /u. long with 

 stipe. 



Bear (1) (rr), Birch (2) (cc), Chain (rr), Chetac (aa), Chetek (rr), Clam 

 (sss), East (rr), Horseshoe (1) (ss), Lindy (rr), Mud (1) (rr), South Crab 

 (ss), Wild Goose (rr). 



An alga that resembles C. stipitatum in the manner of growth but 

 one which is found upon a wider range of genera. It also differs in the 

 curved cells and the broader stipe. 



