AQUATIC VEGETATION 239 
lucens (shining pondweed), entirely submerged ; yellow 
water-lily, mare’s-tail, Prlularia, Myriophyllum. and 
Chara. 
The water of pools which occur on peaty soil contains 
a large amount of soluble organic matter, and the vegeta- 
Fic. 110.—Isoctes lacustris (QUILLWORT). 
tion is characteristic. The most frequent plants are the 
bladderworts, Potamogeton natans, Scirpus fluitans (float- 
ing club-rush), Myriophyllum spicatum, and water-violet. 
