148 



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 (6) transition leaves and (a) water leaves. An axillary shoot (ax) 

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

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



