IV INTRODUCTION. 



of wliicli would be highly interesting, both to the professor and student. 

 Every variety of plant and shrub has its o^\•^x peculiar manner of sustenance 

 in life, req^uiiing different soils, climate, &c. Few, however, possess the 

 power of locomotion ; the natiiral order, Confervce, alone, we believe, enjoy- 

 ing that i)rivilege ; and, perhaps, of all plants, they alone consist of solitary 

 individuals. Other plants are composed of communities, the buds being the 

 inhabitants, the stems consisting of store-rooms and galleries, the little spongy 

 bodies at the extremities of the roots being the true locomotive organs. But 

 as trees do not Vi-alk ujion the surface of the earth, they m other respects ex- 

 liibit abundant instances of spontaneous motion. For example, the ten- 

 dency of plants to incline their stems, and turn the upper surface of their 

 leaves to the light ; the direction which the extreme fibres of the root will 

 often take to escape the light, or to reach the best nourishment ; the folding 

 up of the flower on the approach of rain ; the rising and falling of the water- 

 lily ; and the peculiar and invariable direction assumed by the twining stem 

 ill ascending its prop. 



If a pan of water be placed wiihiu six inches on either side of the stem 

 of a young pumpkin or vegetable marrow, it will in the course of the night 

 approach it, and will be found in the morning with one of its leaves floating 

 in the water. This experiment may be continued nightly, until the plant 

 begins to fruit. 



If a prop be placed within six inches of a young convolvulus, or scarlet 

 runner, it will find it, although the prop may be shifted daily. If after it 

 has twined some distance up the prop, it be unwound and twined in an op- 

 posite direction it wiU return to its original position, or die in the attempt ; 

 yet, notwithstanding, if two of these jdants grow near each other, and have 

 no stake near, on which they can entwine, one of them will alter the direc- 

 tion of its spiral, and they will twine round each other. A very interesting 

 experiment was tried by placing some kidney beans in a cylinder of moist 

 earth : after a short time they commenced to germinate, of course sending 

 the plume upwards to the light, and the root down into the soil. After a 

 few days the cylinder was turned one-fourth round, and again this was re- 

 peated until an entire revolution of the cylinder had been completed. The 

 beans were then taken out of the cyUnder, and it was found that both the 

 plume and radical had bent to accomodate themselves to every revolution, 



