Fig. 57: Echinodorus rostratus: a, mature achene, X 8, b, upper part of inflores- 

 cence, showing maturing burlike fruits, X %; c, whorl of flowers, X %; d, flower, 

 showing the arrangement of the 12 stamens, X 11/l>; e, stamen, X 8; f, habit of mature 

 plant, X %; g, habit of young submersed plant, showing transition stages from early 

 linear to mature cordate leaf blades, X %. (From Mason, Fig. 46). 



