22 LANG, Morphology of the Stock of Isoetes lacustris. 



fact that the production of new leaves and roots proceeds 

 with very little longitudinal growth of the axis. This has 



Fig. 6.— Diagrams to illustrate growth of a convex apex {A), of 

 the apex of Isoetes {£), and of the lower region of Isoetes (C and D). 

 Description in Text. 



been pointed out by Scott and Hill and by other investi- 

 gators, but its effect has not been analysed in detail. In 



