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; b lt >., and 6 3 are 

 the surviving land leaves; the internodes i 1 and i 2 show some elongation as a 

 result of the changed conditions; 6 4 and fc 5 are floating leaves; b G -b 10 are leaves of 

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



