42 



MOVEMENTS OF SEEDLINGS. 



"After a radicle has been deflected by some 

 obstacle, geotropism directs the tip again to grow 

 perpendicularly downwards ; but geotropism is a 



FIG. 6. ZEA MAYS. Radicles excited to bend away from the Little Squares of Card 

 attached to One Side of their Tips (Darwin). See Note. 



feeble power, and here, as Sachs has shown, 

 another interesting adaptive movement comes into 

 play; for radicles at a distance of a few milli- 

 metres from the tip are sensitive to prolonged 



