xiv] 



ISOETES 



59 



There is as a rule little or no difference between the foliage 

 leaves and sporophylls; in /, lacustris the latter are rather 



Fig. 132. Isoetes echinospora (After Motelay and Vendry^s). 



A. Stem of I. lacustris. 



B. Base of sporophyll: I, ligule ; spy, sporangium partially 



covered by velum. 



