tionably a plant previously described by Borge as Ulothrix monili- 

 formis. Although our plant has the cell shape of the latter species 

 and is approximately the same size, it differs in the arrangement of 

 the cells. Ulothrix moniliformis Borge possesses cells in continuous 

 filamentous arrangement inclosed by a sheath. All of the Wisconsin 

 specimens had the cells arranged in crooked filaments in linear 

 groups of 4, each group with an individual sheath. Occasionally the 

 cells showed a tendency toward an irregular bilateral arrangement. 

 The chief objection to placing the Wisconsin species in Hormidiopsis 

 is the presence of a pyrenoid. The cell shape and arrangement would 

 seem to preclude the assignment of this species to Geminella. Addi- 

 tional observations and life history studies are necessary before the 

 plant can be satisfactorily identified. 



Found in a Sphagnum bog lake intermingled with other algae. 

 Wis. 



BINUCLEARIA Wittrock 1886, p. 9 



Filaments of long cylindrical cells. Protoplasts short-cylindric or 

 oblong with rounded apices; not filling the cell, but surrounded by 

 lamellated mucilage, which fills the space between the protoplasts 

 and the end walls. Protoplasts in pairs (as a result of their remaining 

 close together after cell division) separated by a thin cross wall. 

 Chloroplast laminate, forming a band in the midregion of the cell; 

 without pyrenoid. 



Binuclearia tatrana Wittrock 1886, p. 9 



PL 7, Figs. 7-9 



Cells 7-10/i. in diameter; the length sometimes as much as 6 times 

 the width. 



Common in acid bogs and soft water lakes; appearing quite fre- 

 quently in small pools and ditches where the water is shallow and 

 where there is an abundance of organic matter. Mich., Wis. 



RADIOFILUM Schmidle 1894, p. 47 



Filaments either unbranched or branched, the branches sometimes 

 anastomosing to form a series of links. Cells lenticular, spherical, or 

 oblate-spheroidal, dividing in 1 or 2 planes. The cell wall (at least in 

 some species) composed of 2 cups or helmet-shaped halves, which 

 adjoin in the midregion to form a transverse rim around the cell, at 

 which point cell division occurs, new cell halves being interpolated 

 between the older parts of the cell wall. Chloroplast a parietal plate, 



[102] 



