FIELD BOOK OF PONDS AND STREAMS 



the flower cup without brushing the pollen from them. The 

 mucky waters in which they grow are full of dragonfly and 

 damselfly nymphs which climb up them to shed their skins, 

 often returning as adults to lay their eggs on the stems just 

 below the water surface. 



Fig. 72. — Water stargrass, Heteranthera diibia. 



Water stargrass, Heteranthera dubia. — This is a plant of 

 the muddy shoals with roots in the mud, its grass-like leaves 

 submerged in the water. The small yellow flowers blossom 

 at the surface, growing from leafy thread-like tubes on the 

 sides of the leaf stems. (Fig. 72.) 



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