LESSONS WITH PLANTS 



339 



litches, may be shown with the compound miscroscope. 

 These httle unicellular plants have the power of locomotion. 

 Dn moist earth in ditches there is often a coating of bluish- 

 ;reen algae, the Oscillatoria, which also have some power 

 )f movement. There are 

 ;pore-cells set free by 

 nany plants that swim 

 ictively about, and are 

 reproductive devices. 



Though the larger 

 slants may not move 

 ibout, yet they can move 

 ;heir various parts. A 

 :ew observations on 

 growing plants will show 

 hem to be thoroughly 

 ilive and active. 



In a glass germinator 

 'see p. 300) notice how 

 he roots of seedKngs 

 P'ow down. Invert the 

 ;erminator. Note that 

 n a day or so the roots 

 lave turned and now grow downward again 

 mow enough to grow down. 



Note also how a rootlet bends away from and around an 

 )bstruction, such as a pebble placed in its course. The 

 oot is sensitive to touch and responds by a curvature. 



Plant a sunflower or other seedling in the drain hole of a 

 mail flowerpot full of earth and hang it up somewhere. Note 

 hat soon the stem curves upward. The same may be shown 



Fig. 136. Squash Seedling Laid on its Side has 

 Straightened up Again. 



They seem to 



