196 FRESH-WATER ALGJE OF THE UNITED STATES. 



GLOEOCYSTIS AMPLA, Kg. 



Thallus gelatinous, rounded, lobed, dirty or bright green. 

 Cells globose or rounded oblong, 2-4-6, or more, associated 

 in families ; tegument colorless, gelatinous, distinctly con- 

 centrically lamellose, contents green granular. 



Diameter of cells, 9-15 /x 

 Diameter of families, 45-90 yw. 



Syn. Gloeocapsa ampla, Kg. ; Pleurococcus swperbus, Cienk. 

 Attached to submerged plants, or free swimming. 



Plate CLXVI, figs. 2-8, varieties in size of cells, size of 

 cysts and number of cells in cyst, and maternal cell. 



GLOEOCYSTIS VESICULOSA, Naeg. 



Probably merely a variety of G-. ampla; in all respects the 

 same except size. 



Diameter of cells, 4-7 /u. 



Diameter of families, 35 //, more or less. 



& 



More frequently on old wood and stones in ponds. 

 Plate CLXYI, figs. 9-15. 



GLOEOCYSTIS EUFESCENS, A. Br. 



Another form of G. ampla, differing from the last merely 

 by a change of color, which is sometimes brownish yellow 

 or reddish. 



Plate CLXVI, figs. 16-18. 



On water plants, pools and ponds. 



GLOEOCYSTIS RUPESTRIS, Bab. 



Cells smaller, as of G. vesiculosa, tegument not so wide and 

 not so lamellate. Thallus dull green or olivaceous, gelati- 

 nous, rather firm. 



Diameter of cells, 3-5 /u. 

 Moist rocks and walls. 

 Plate CLXVI, figs. 19-21. 



Genus 61, NEPHROCYTIUM, Naeg. 



Cells oblong, kidney -shaped, with a dorsal chlorophylose vesi- 

 cle, 2-4-8-16 associated in free swimming families surrounded 

 by an ample oval or kidney-shaped tegument. Very variable 

 in size. 



