342 



NATURE-STUDY 



themselves firmly. The climbing nasturtium has no ten- 

 drils, but its long leaf-stalks twist themselves about the 

 support and hold up the plant. 



The morning-glory, the hop, and other 

 twining plants should be observed as 

 they climb on their supports. A young 

 morning-glory may be seen to apparently 

 feel around for something to climb upon. 

 When it touches such a support, as it 

 swings around with its tip, it seems to 

 feel, and then grows spirally around the 

 same. 



The extreme of sensitiveness in plants 

 may be seen in the plant very properly 

 called the sensitive plant. This may be 

 obtained at the greenhouses, or raised 

 from the seed. Slightly touching one of 

 the leaflets will cause it and the other 

 leaflets in the compound leaf to fold to- 

 gether against the midrib. By greater 

 agitation the whole plant may be made 

 to fold up. 



Plant Distribution and Seed Dispersal 



Plants have their wanderings and mi- 

 FIG. 138. Moming-giory. g ra tions just as the races of men. That 

 many plants produce motile spores, and that . some algae 

 have the power of locomotion, has been mentioned. But 

 the higher plants, though they may remain fixed as individ- 

 uals, still make extensive wanderings as a race or species. 

 The races of man have become distributed over nearly 



