Fig. 289: Spirodela oUf;orhizo: a. habit, X 2; b and c, root tips, with and without 

 rootcaps, the rootcap 1.2-1.9 mm. long, X 20; d, pistillate flowers and pair of staminate 

 flowers enclosed by short spathe open on one side, X 40; e, habit, lower surface, show- 

 ing the large netlike air spaces and the flowers and fruit arising from pouch. X 4; f, 

 fronds, top view, with flowers and fruit, X 4; g and h, fronds remaining attached to 

 one another by slender stipes, X 4; i and j, fruits, showing the winged shoulders, X 16; 

 k and 1, seeds, ribbed and minutely reticulate, X 16; m and n, frond (longitudinal sec- 

 tion), showing air chambers, X 8. (From Mason, Fig. 163) 



