22 NATURE STUDY. 



Fifth. To absorb gases and make plant food, with 

 the aid of the sun. 



Wonderful as is the flower considered as a structure, 

 it becomes much more wonderful when studied as a 

 living thing, an organ with a work to do, an adapta- 

 tion to work and environment. 



In particular the slender, hollow flower stem is an 

 admirable illustration of adaptation to work or function. 

 In the bud it is very short, lengthening, as the flower 

 develops, just enough to push the blossom above the 

 grass, and later lengthening much more to lift the 

 plumed seeds up where they will catch the wind. 

 The length of the stem depends largely on the height 

 of the grass or other plants about it; in tall grass it 

 may push up two feet or more to lift flower and seed 

 above surrounding plants. In the late autumn, when 

 little is to be gained and much may be lost by lifting up 

 the flower, the flower stem, or scape, remains very short. 

 It bends away from shady places. Its structure, a 

 hollow cylinder, gives the greatest strength and flexi- 

 bility with the least material. 



The scape not merely lifts the seeds up into the 

 wind, but when they are ripe the rapid change in the 

 form of its upper end, or receptacle, from a shallow 

 cup to a somewhat flattened ball, causes the seeds at- 

 tached to it to spread out into the hairy sphere, and 

 exposes every seed with its little parachute to the 

 wind. (See frontispiece. Compare Figs. A, 5, and B.) 



The scape has one duty, to hold up the flower toward 

 the sun, and where it will attract insects, and to lift up 



