HETEROPHYLLY 



CH 



FIG. 104. Potamogetonfluitans, Roth. A land plant transferred for about a month 

 to distilled water with no substratum and the adventitious roots repeatedly re- 

 moved. The internodes marked I were formed during land life; fej, > 2 and 6 3 are 

 the surviving land leaves; the internodes i^ and 2 show some elongation as a 

 result of the changed conditions ; 6 4 and 6 5 are floating leaves ; b Q -b w are leaves of 

 the submerged type. [Esenbeck, E. (1914).] 



