OF NATURAL HISTORY. j 



coverable in the vegetable kingdom. When the roots of a tree 

 meet with a ftone, or any other obflrudion to their motion, 

 in order to avoid it, they change their former diredlion. They 

 turn from barren to fertile earth, which indicates fomething analo- 

 gous to a feledion of food. Like the polypus, plants, when con- 

 fined in a houfe, uniformly bend toward the window or aperture 

 through which the rays of light are introduced. 



The fenfitive plant poflefTes the faculty of motion in an eminent 

 degree. The flighteft touch makes its leaves fuddenly fhrink, and, 

 together with the branch, bend down toward the earth. But the 

 moving plant, or hedyfarum movens, of which there are fpecimens 

 in the botanic garden of Edinburgh, furnifhes the moft aflonifliing 

 example of vegetable motion. It is a native of the Eaft Indies. Its 

 movements are not excited by the contadl of external bodies, but 

 folely by the influence of the fun's rays. The motions of this plant 

 are confined to the leaves, which are fupported by long flexible foot- 

 ftalks. When the fun ihines, the leaves move brifkly in every direc- 

 tion. Their general motion, however, is upward and downward : 

 But they not unfrequently turn almoft round j and then their foot- 

 ftalks are evidently iwifted. Thefe motions go on inceflantly as 

 long as the heat of the fun continues : But they ceafe during the 

 night, and when the weather is cold and cloudy. Our wonder is 

 excited by the rapidity and conftancy of the movements peculiar to 

 this plant. The frequency, however, of fimilar motions in other 

 plants, renders it probable that the leaves of all vegetables move, or 

 are agitated by the rays of the fun, though many of thefe move- 

 ments are too flow for our perception. 



The American plant called dionaea mufcipula, or Venus^s fiy-trap^ 

 affords another inftance of rapid vegetable motion. Its leaves are 

 jointed, and furnifhed with two rows of ftrong prickles. Their, 



furfacea- 



