i 4 8 



HETEROPHYLLY 



[CH, 



FIG. 96. Hippuns vulgaris, L. A shoot which was found lying horizontally in the 

 water, August 17, 1917. It had produced air leaves (c), but presumably in very 

 heavy rains, which had terminated a fortnight earlier, it had been beaten down 

 and had produced (b) transition leaves and (a) water leaves. An axillary shoot (ax) 

 bore water leaves. (J nat. size.) Fig. 96 should be compared with Fig. 151, 

 p. 231, which shows the normal relations of the two leaf types. [A. A.] 



