VARIOUS MOVEMENTS OF PLANTS 109 



sensitive plant (Fig. 112). The normal position of 

 the leaf is shown at the right. A slight touch 

 or shock causes the petiole to drop and the leaf- 

 lets to shut up, as shown on the left. The move- 

 ments are rapid and striking. 



142a. The sensitive plant (Mimosa pudica) is easily grown 

 from seeds, which may be obtained of seedsmen. It thrives wher- 



FIG. 112 

 The curious behavior of the sensitive plant. 



ever beans will grow. The young plants, which grow rapidly, are 

 more sensitive than old ones. The sensitive plant is one of the 

 Leguminosae. 



143. We have now seen movements in stamens 

 (Fig. 61), in leaves, the opening and closing of 

 flowers, the shoots of twining plants and of ten- 

 drils, the fly -catchers of insectivorous plants, of 

 stems towards light, and roots towards the earth 

 (Obs. xvii.) and darkness (137). There are move- 

 ments in the bursting of pods; and there are 

 other movements which we have not considered. 

 Plants are not as fixed and as unresponsive to 

 external conditions as we have thought them to be. 



