70 Trees, Stars, and Birds 



many forest trees lack the corolla, or group of petals, 

 which makes the blossoms of fruit trees so attractive. 

 They have, however, the essential parts of the flower, 

 the stamens and pistils. The stamens of flowers produce 

 a yellow powder called pollen. In the lower part of 

 the pistil, called the ovary, the ovules (little eggs) which 

 are to grow into seeds are produced. 



Seeds cannot be produced by trees or other plants 

 unless pollen from the same kind of tree or one very 

 similar falls on the tip of the pistil, which is called the 

 stigma. The stigma is covered with a sweet, sticky 

 liquid, and the pollen grain, when it lodges upon the 

 stigma, absorbs the liquid and grows into a tiny plant 

 which extends down inside the pistil to the ovary. In 

 the lower extremity of this tiny plant is a minute cell 

 which unites with an egg cell that grew in the ovary. 

 This union is called fertilization. After it has taken place, 

 the egg cell divides, giving rise in time to a number of 

 cells so arranged as to form an embryo with tiny stem 

 and leaves. By examining acorns, beans, or other seeds 

 that have been softened by soaking them in water, you 

 can find the embryo. This is the part of the seed that 

 grows into a plant like the plant from which the seed 

 came. 



SECTION COROLLA CALYX 



FIG. 41. The parts of a complete flower. 



