Fig. 295: a-d, Wolffia papulifera: a, dorsal view, about X 40; b and c, lateral view, 

 X 40; d, longitudinal section, X 40. e-g, Wolffia columhiano: e, dorsal view, about X 40; 

 f, lateral view, X 40; g, cell, greatly enlarged to show stoma. (Courtesy of R. K. 

 Godfrey). 



