36 MOVEMENTS OF SEEDLINGS. 



have described a circle, or rather, as the stem is 

 always growing upwards, a circular spiral. But it 

 generally describes irregular elliptical or oval fig- 

 ures ; for the apex, after pointing in any one direc- 

 tion, commonly moves back to the opposite side, 

 not, however, returning along the same line. . . . 



" In the course of the present volume it will be 

 shown that apparently every growing part of every 

 plant is continually circumnutating, though often 

 on a small scale. Even the stems of seedlings 

 before they have broken through the ground, as 

 well as their buried radicles, circumnutate as far 

 as the pressure of the surrounding earth permits. 

 In this universally present movement we have 

 the basis or groundwork of the acquirement, ac- 

 cording to the requirements of the plant, of the 

 most diversified movements. Thus, the great 

 sweeps made by the stems of twining plants, and 

 by the tendrils of other climbers, result from a 

 mere increase in the amplitude of the ordinary 

 movement of circumnutation." 1 



After minute descriptions of many experiments 

 on the movements of radicles and cotyledons of 

 seedlings, he says : 



" In all the germinating seeds observed by us, 

 i p. 3. 



