156 Field, Forest, and Wayside Flowers 
For if such vegetable friends are wantonly re- 
moved, or are allowed to perish, valuable tracts of 
ground are buried under sand, or are altogether 
washed away, and harbors are rendered unsafe by 
accumulating shoals and bars of sand or mud, 
brought from other shores. 
Some species of grass, in the course of many 
summers, convert marshes and _half-submerged 
shores into firm land, and hence have been called 
“Nature’s most valuable colonists.” 
They hold territory which has been wrested from 
the waters, and which, but for them, would speedily 
be retaken. 
Thus they fix, if they do not change, the 
bounds of land and sea, and help to make geog- 
raphy for the boys and girls of coming generations. 
To the evolutionary botanist the grasses are pe- 
culiarly interesting, for while many of their charac- 
teristics show the highest possible adaptation to 
the conditions of their lives, their flowers are con- 
spicuous instances of degeneration. 
They have reached, it seems, the last stage in a 
strange, eventful history. It is surmised that the 
first flowers ever born into the young world had 
stamens only, or a pistil only, as the case might 
be, had neither calyx nor corolla, and were wind- 
