HOW TO KNOW THE FRESH-WATER ALGAE 



229b Chloroplast a broad plate extended over most of the cell wall; 

 aquatic. Fig. 163 HORM1DIOPSIS 



^*a Fig. 163. Hormidiopsis ellipsoide- 



•&\ um Pres. 



mirk S\ G> 



j£*% Cx) % xj\$¥ ) £k This is the only species reported 



O^^C/^ nfi/ from this country and possibly 



A r?sa\ 7v-\ cannot be differentiated from Hor- 



'^x^r^Q'Q® (&&l(w ®&. midium (Fig. 168) except that the 



\jjj^ Sg$ \^AJy filaments are frequently interrupt- 



1<3 ed and constricted at the joints, 



Figure 163 ' 



the cells being oblong or oval 

 rather than cylindrical. Characteristically, the chloroplast extends 

 but only part way around the cell wall. 



3S5 



230a Filament composed of units which include 2 oval or subspherical 

 protoplasts; the space between protoplasts and the walls filled 

 with layered (lamellose) material. Fig. 164 BINUCLEAR1A 



Fig. 164. Binucleaiia tatrana 

 ^~ &C% T (TY& Wittr., one filament show- 



ing a gelatinous sheath. 



This is the only species 

 reported from the United 

 States; occurs intermingled 

 with other filamentous algae, 



Figure 164 



especially in mixtures taken from bogs. The paired protoplasts within 

 each unit of the filament make it easy of identification. 



230b Filaments of cells without paired protoplasts as above 231 



231a Filaments with a gelatinous sheath 232 



231b Filaments without a gelatinous sheath 235 



232a Cells cylindric-quadrate, globose or ellipsoid; adjoined at the 

 end walls 233 



105 



