POLLINATION 17 



at once increased. If the weather, when fruit trees are in 

 bloom, is so cold or rainy that the bees do not fly from 

 flower to flower, the crop of fruits is usually small. 



Cross-pollinated plants (those that need to get pollen 

 from other plants of the same kind) can be divided into 

 two classes, first, those whose pollen is carried from one 

 plant to another by wind ; second, those whose pollen is 

 carried by insects. 



Why strawberries sometimes fail to bear. A gardener 

 once had a well-worked strawberry bed that showed a 

 mass of leaves and runners, but yielded 

 few berries. This was because he had 

 planted only one variety, and that one 

 variety did not have well - developed 

 stamens. His patch of strawberries 



would have borne good crops if he had _ 



FIG. 16. FLOWER 



planted every fourth row with another or STRAWBERRY 



variety having stamens as well as pistils. WITH BOTH PISTILS 



J AND STAMENS 



From this you see it pays to know some- 

 thing about how plants are supplied with pollen. Imper- 

 fect varieties of strawberries are called pistillate varieties, 

 because they have pistils only, and the perfect kinds are 

 called staminate or perfect varieties, because they have 

 stamens as well as pistils (Fig. 16). 



Why the fruit crop sometimes fails. Even when the 

 flowers contain both stamens and pistils, there is often a 

 failure to produce fruit. This is likely to happen when a 

 single variety of grapes, pears, or apples is planted alone 

 and away from all other varieties of the same fruit. 

 Some varieties of these fruits must get pollen that has 



