PRAIRIE FLOWERS IN AUGUST 



MATERIAL : Several species of goldenrods, blazing star, wild sun- 

 flowers, cultivated sunflowers, prairie weeds; several kinds of aquatic 

 plants for comparison. If no wild prairie is accessible, a piece of high 

 ground not covered by trees or rank road-weeds will do for the intro- 

 ductory field lesson. Strips of wild prairie can often be found along 

 railroad tracks. 



27. Some weeks ago we spent considerable time in 

 studying plants and animals found in wet places or in the 

 water. To-day we shall take up a group of plants which 

 make their homes in open fields and on dry prairies. Here 

 in my left hand I hold the flowers we picked yesterday 

 along the railroad track, and in my right hand I hold some 

 of our friends from the lake bottom. You all have similar 

 specimens on your desks. Notice the difference in the 

 general texture. The aquatic plants are soft, easily cut 

 and compressed. Try to make them stand upright. In 

 their lake home they grew erect, because the water buoyed 

 them up, but in the air they fall over and shrivel up. 



If you make cross and longitudinal sections of stems and 

 leaves of aquatic plants, you can see quite well that their 

 whole tissue is composed of cells. All vegetable tissue is 

 composed of similar cells, but in most other plants the cells 

 are much smaller, are closely packed, and often have com- 

 paratively thick walls, which make the plant hard and 

 rigid. 



Observations. What weeds do you find growing along roads, in fields, 

 on vacant lots, and in other waste places? 



50 



