Pond Societies 33c 



bur-reed (Sparganium) , of bulrush (Scirpus), of spike- 

 rush (Eleocharis) , of water plantain (Alisma), of arrow- 

 head (Sagittaria) , and arrow-arum (Peltandra, of pick- 

 erel-weed (Pontederia), of manna grass (Glyceria), etc. 



2. The intermediate zone of surface aquatics will 

 include such as: 



(a). These rooted aquatics with floating leaves: 

 white water-lily (Castalia), spatterdock (Nymphcea), 

 water shield (Brasenia), pondweed (Potomogeton), etc. 



Fic. 196. A spray of the sago pondweed, Potamogeton, coated with 

 sUme-coat diatoms, its leaf tips bearing dweUing tubes of midge 

 larvas (Chironomus). 



