MOVEMENTS OF SEEDLINGS. 



39 



" The growing part, therefore, does not act like a 

 nail when hammered into a board, but more like 

 a wedge of wood, which whilst slowly driven into 



FIG. 5. SPLITTING OF A ROCK BY THE GROWTH OF THE ROOT OF A LARCH. 

 (" Pflanzenleben.") 



a crevice, continually expands at the same time by 

 the absorption of water ; and a wedge thus acting 

 will split even a mass of rock" (Fig. 5). 1 



1 " The great force exerted by the increase in size of the stems and 

 roots of woody plants is sometimes demonstrated in an extraordinary 



