234 



BOTANY FOR BEGINNERS 



CHAP. 



receive the name of burrs. The hooked fruit of the Wood 

 Avens clings to animals, and is carried for great distances. A 



country walk through a district 

 where these plants grow will best 

 show how their fruits are distri- 

 buted by animals. 



Seeds Scattered by Ani- 

 mals. When seeds are distributed 

 by passing through the alimentary 

 canal of animals, they must possess 



C\ "** two characters, (a) The seed must 



^^^r- J^l ^ e protected by a hard portion of 



// the fruit, which is not acted upon 



by the digestive juices during the 

 passage of the fruit through the 

 alimentary canal, (ff) The hard 

 part of the fruit must be surrounded 

 by something eatable to tempt the 

 animal to swallow it. The drupes 

 of the Cherry, Blackberry, and 

 Raspberry, are scattered by birds 

 eating them and afterwards drop- 

 ping the seeds. As a rule, plants which produce fruits that are 

 adapted for distribution in this way produce succulent fruits, as 

 the Apple, Strawberry, Rose-hips, and Currant. 



(Termination of Seeds. The conditions necessary for 

 the germination of seeds have already been considered (p. 152). 

 That seeds have their vital functions arrested by drying is 

 familiar to everyone ; but when seeds are placed under suitable 

 conditions germination soon begins. Seeds and fruits are able 

 to find a permanent lodgment in the soil by the structure of 

 their surfaces. Thus, the fruits of the Geranium and Grasses 

 are enabled to bury themselves in the ground by movements 

 which are produced by changes in the amount of moisture they 

 contain. The Ivy-leaved Toadflax, or Mother of Thousands, 

 buries its seed capsules in the crevices of walls and cliffs. Nuts, 

 Acorns, and similar seeds are often buried in the ground by 

 animals, such as the squirrel, and forgotten. Afterwards they 

 may germinate. Some seeds have mucilaginous coverings, 

 which not only fix them to the soil but absorb water. 



FIG. 233. Fruit of Wood Avens. 

 A, the fruit, showing the hook 

 H ; B, the fruit, with both 

 style and stigma ; C, the style 

 and stigma more highly magni- 

 fied. The hook is formed from 

 the style by the stigma break- 

 ing away. 



