592 



Smith: Notes on the Vegetation of Ponds. 



except in rainy seasons, when there will be some inflow at the 

 southern end, and the pond will attain its maximLim depth when 

 the water begfins to pass through the outflow. The dominant 

 plants differ from those of the Boif-bean pond — there is no Bog-- 

 bean nor Water Parsnip, but Pondweed and Water Plantain 

 have a place. The plants are arranged in four well-marked 

 zones, viz. : (c/) a marginal zone of taller species of Rushes 



^i/ 





^fOcA.f^l,<? 





If *^^ 



^r: Bur-reed. 



= Pondweed. 



rji Water Plantain. 



■:^ Water Dropwort. 



i = 



Rushes. 



(Further explanation 

 in text.) 



Fig. 2. — The Pondweed and Water Plantain Pond. 



(/uncus) ; (b) a zone of Water Dropwort [CEnanthe Jistulosa), 

 mixed with Water Plantain [Alisma Plantago) at the southern 

 end ; (c) a zone of Bur-reed (Sparganium) also mixed with 

 Water Plantain ; {d) a central patch of Pondweed {Potamogeton 

 nutans). The Pondweed lies in the centre towards the northern 

 end ; its leaves were large, and with long leaf-stalks, such as 

 occur in deep water. From this we suspect that the Pondweed 



Naturalist, 



