142 ORGANS OF VEGETATION 



branches of willow or poplar trees that have been severed from 

 the parent stem frequently live for months and occasionally form 

 new leaves. In spite of the popular opinion, however, the foliage 

 of ordinary plants does not usually absorb much of the water 

 that falls upon it as rain, or that is deposited upon it as dew. In 

 fact many leaves shed the water as fast as it falls on them. Hence 

 in watering plants our care should be to apply the water in such a 

 way that it will come in contact with the roots of the plant rather 

 than with its leaves. 



Another fact that we should not overlook is the power of the 

 leaves of the plant to radiate heat. Experiments show that they 

 radiate heat more readily than the soil. After a clear night we 

 are likely to see grass fields loaded down with a heavy dew, while 

 the adjoining bare land will be dry. 



Leaves of the plant also play an important part by shading 

 the ground and protecting it from the drying influence of the sun's 



rays. In many cases the leaves 

 protect the soil against the 

 drying influence of the wind, 

 which has less ready access to 

 shaded land than to bare and 

 exposed land. 



The Flower. The most at- 

 tractive part of nearly every 

 plant is the flower, which ap- 

 peals so strongly to us through 

 its beauty and fragrance. 



Parts of a flower. From the flower comes the 



P, petal; SEP, sepal; S, stigma; St, stamen. ,. . , . . . . , ,. , 



fruit so highly prized as food 



and the seed so necessary for the reproduction of plants. 

 Every complete flower consists commonly of a circle of greenish 

 leaves forming an outer envelope called the calyx, and an inner 

 circle of bright-colored leaves forming an inner envelope called 

 the corolla. This envelope is generally of some other color than 

 green. Each leaf of the calyx is called a sepal, and each separate 

 leaf of the corolla is called a petal. 



Within the corolla we find a row of slender organs called stamens; 

 and in the center of the flower, surrounded by the stamens, we 



