134 



UNDER THE OPEN SKY 



What an important part it is these swamp 

 plants have to play! No sooner is a stream 

 dammed back by any obstruction than Na- 

 ture tries to fill up the lake so formed. 

 From the hills above and around she brings 

 her mud and dumps it into the upper end 

 of the lake. The first high water would 

 wash it all farther down did she not bind 

 the soil firmly in place. For this purpose 

 she uses swamp plants. The spatter-dock 

 and the arrow-leaf grow well out in the 

 water, and induce the first settlings of mud 

 about their roots. Then come the cat- 

 tails, with leaves erect and yet yielding 

 enough to stand an occasional flood, and 

 about their roots the soft ooze falls in a 

 tenacious mass. Still farther back stand 

 the bristling clumps of sedge, binding down 

 the soil the others have gathered, but al- 

 lowing runways for the water when it is 

 high. These are followed by the sheet of 

 lush meadow grasses, pinned down firmly 

 with deep anchors of skunk-cabbage, every 

 good-sized clump of which puts down about 

 a hundred roots, each as thick as a lead- 



