44 



THE BOTAmCAL MAGAZINE. 



[Vol, XXV. No. 289^ 



are not found at other places on account of various causes 

 which will be explained later. On the contrar}^, Typha angasti- 

 folia occurs as a characteristic plant everj-where in this 

 zone. 



4. Zone of Phragmites communis Trin. 



This zone follows indistinctly outside the foregoing, but 

 Typha and Zizania diminish gradualh' landward and at last 

 give wa}^ to a large pure association of Phragmites communis 

 on the shore. When deep humus soil occurs here, it is inter- 

 mingled with the swimming plants as Liwnanthenium nym- 

 phoides var. Japonica, Hydrilla asiatica, and especially Nymphsea 

 tetragona var. angustata. On the bank it is mixed with Salix 

 purpurea L. and S. nipponica Fr. et Sav. 



The three last zones of marsh plants (helopln^tes) extend 

 from the depth of about 1.7m to the shore averaging the width 



> 







Fig. G. 



Z ine of Phragmites communis, associated with tl.e liixnriaiU vegetation 

 of Nymphica ieiiagona var. angustata. 



