18 



FLOWERS. SEED PRODUCTION 



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planted near together in the same orchard. The same is some- 

 times true in such other fruits as pears, plums, peaches and straw- 

 berries. 



Wind Pollinating. Usually pollen is carried either by wind 

 or by insects. Flowers in which the wind is the chief force to aid 

 in cross-poll ena ting have certain characteristics. Usually the 

 pollen is light and dry. The flowers themselves are inconspicuous 

 as to color, but may be placed where the wind can easily strike 



them. There is no odor or 

 nectar present. Examples of 

 the class are corn, grasses and 

 grains. 



Insect Pollinating. Many 

 of our cultivated plants are 

 dependent upon the work of 

 insects in transporting the 

 pollen from one flower or plant 

 to another. Bees, flies and 

 other insects aid greatly in this 

 work. Flowers which are de- 

 pendent upon insects to carry 

 the pollen have some or all of 

 the following characteristics- 

 (a) Sticky, heavy pollen, (b) 

 Showy flowers, (c) Fragrance 

 and nectar (Fig. 11). (d) Some- 

 times special structures to ac- 

 commodate the insects. An ex- 

 ample of the special structure 

 is found in sweet pea blossoms. 

 When the insect alights upon 

 the limb of the flower the pol- 

 len is brushed from the coat of the insect by the stigma surface. 

 As the insect leaves the flower other pollen is scattered by the 

 stamens upon the coat of the insect to be carried to other flowers 

 (Fig. 12). 



Growth of Seeds. After pollination takes place the ovules 

 usually develop rapidly and mature seed may be formed in a 

 very short time. The period elapsing from the time the timothy 

 field is in blosson until the seed is ripe is only a few weeks. This 

 is noticeable also in wheat and other small grains. During this 



FIG. 11. Larkspur flowers bear nectar 

 in the deep "spur," to attract insects. The 

 latter carry pollen from flower to flower, and 

 they are "cross-pollinated." (U. S. D. A.) 



