falcatum has a long, colorless apical beak not present in the former 

 species. It should be compared also with Characiopsis longipes. 



On filamentous algae in shallow water of lake margins; swamps. 

 Mich., Wis. 



Characium gracilipes Lambert 1909, p. 65 

 PI. 45, Fig. 16 



Cells elongate cylindric, straight or very slightly curved, abruptly 

 tapering anteriorly and extended to form a long, hyaline hair, and 

 abruptly tapering below to a slender stipe with 2 or 3 fine, rhizoidal 

 branchings at the base; chloroplasts variable, 1-32 in number with 

 a single pyrenoid in each; cells 5-1 4/^ in diameter, (70)-80-480fi long. 



Epizoic on the anterior appendages of Crustacea. Mich., Wis. 



Characium Hookeri (Reinsch) Hansgirg 1888, p. 123 



PL 45, Fig. 17 

 Cells mostly gregarious on Cyclops, club-shaped to subcylindric; 

 stipe long or short, without an attaching disc; chloroplast 1, vdth 1-3 

 pyrenoids; cells 9-1 2/x. in diameter, 27-30)u. long. 



On Cyclops in lakes and ponds; euplanktonic and tychoplanktonic. 

 Wis. 



Characium limneticum Lemmermann 1903c, p. 81 

 PI. 45, Fig. 18 

 Cells fusiform or lunate (rarely almost straight), extended an- 

 teriorly into a long, sharp, spine-like tip, tapering posteriorly rather 

 abruptly to form a long narrow stipe, without a basal attaching disc; 

 chloroplasts 1-8, arranged to form a series of parietal bands; cells 

 5-14yu, in diameter, 25-110/i, long, including stipe. 



Epizoic on Diaphanosoma hrachyura in lakes. Mich., Wis. 



Characium obtusum A. Braun 1855, p. 39 

 PI. 45, Fig. 20 

 Cells oblong-ovate; stipe short and fairly thick; cell rounded 

 anteriorly and furnished with a thickened plug at the apex; chloro- 

 plast parietal, with a single pyrenoid; cells (8)— 10— 12ju, in diam- 

 eter, 12.9-14.8- (33)/. long. 



Attached to filamentous algae; lakes and Sphagnum bogs. Mich., 

 Wis. 



Characium operculum Ackley 1929, p. 304 



PI. 46, Fig. 13 

 Cells broadly pyriform on a short thick stipe wdth a basal 

 attaching disc, broadly rounded anteriorly and furnished with an 



[217] 



