FEB. 1911.] NAKANO.—THE VEGETAT. OF LAKES AND SWAMFS. 



41 



well as in the next zone. Among a loose association of Zizania 

 aquatica, it is very sparsely found Limnanthemum indicum 

 Griseb. Here occur also many species of the preceding zone and 

 especially such as Ceratophyllum demersum, and Najas minor. 



Zone of Zizania aqualica. 

 Swimming liydrophyte {Limncnthemum indicum) among Zizania aqualica; 

 landward follows directly Fhragmites-zone, owing to tlie absence of 

 Typha-zoY.e. 



3. Zone of Typha angusti folia. 



This zone comes immediately outside the preceding zone. 

 The depth here measures about Im in average. The favorable 

 movement and depth, of water has evoked the dense growth of 

 Zizania aquatica, and consequently has given a happy residence 

 for Typha angustifolia Bory et Chamb., Scirpus Tabern^- 

 iMO/2 tai32 Gmel., and for many swimming hydrophytes. Among 

 the latter the most luxuriant plants are -.—Nymphaea tetragona 

 Georg. var. angustata Casp., Limnanthemum indicum Griseb. 



