152 NATURE TEACHING 



proceeding, namely, an animal eating its fruit. Many 

 of the fruits of this class have been greatly altered in 

 character by cultivation and selection by man, who has 

 increased the pleasant edible portion, even to the sup- 

 pression of the seeds ; for instance, bananas, pineapples, 

 seedless oranges, seedless grapes, etc. 



The mistletoe, which has a fleshy berry much 

 eaten by birds, has an interesting method of seed 

 dispersal. Its seeds are extremely sticky, and when a 

 bird eats the fruit the seeds adhere to its bill. The bird, 

 sooner or later, cleans its bill by rubbing it against the 

 bark of the tree on which it has been feeding, or of some 

 other tree to which it has since flown. The seeds stick, 

 and after germination pierce the bark and so establish 

 themselves. Mistletoe once introduced into an orchard 

 may thus spread from tree to tree and become a trouble- 

 some pest. 



Explosive fruits. There are some fruits which possess 

 power of themselves to throw their seeds to some 

 distance. Sitting on a hot August day by a furze bush 

 we may often here a crackling sound, caused by the ripe 

 pods bursting open, when the two halves twist up 

 and throw out the seeds. The fruits of the violet when 

 ripe "flip" out the seeds, owing to the sides of the 

 seed-box pressing on the smooth seeds, so that they are 

 shot out just as we can flip a wet apple-pip between 

 thumb and finger. 



The garden balsam and the wild oxalis have special 

 kinds of fruits which, when ripe, throw out the seeds to 

 some considerable distance. 



