VEGETATIVE OKGANS OF PLANTS. 263 



than the outer ones. Finally, in a vessel where the fer- 

 tilizer was placed in a horizontal layer at the bottom, 

 the roots extended through the soil, as attenuated and 

 slightly branched fibers, until they came in contact with 

 the lower stratum, where they greatly increased and ram- 

 ified. In all cases, the principal development of the 

 roots occurred in the immediate vicinity of the material 

 which could furnish them with nutriment. 



It has often been observed that a plant whose aerial 

 brunches are symmetrically disposed about its stem, has 

 the larger share of its roots on one side, and again we find 

 roots which are thick with rootlets on one side and 

 nearly devoid of them on the other. 



Apparent Search for Food. It would almost appear, 

 on superficial consideration, that roots are endowed with 

 a kind of intelligent instinct, for they seem to go in 

 search of nutriment. 



The roots of a plant make their first issue independ- 

 ently of the nutritive matters that may exist in their 

 neighborhood. They are organized and put forth from 

 the plant itself, no matter how fertile or sterile the me- 

 dium that surrounds them. When they attain a certain 

 development, they are ready to exercise their office of 

 collecting food. If food be at hand, they absorb it, and, 

 together with the entire plant, are nourished by it they 

 grow in consequence. The more abundant the food, the 

 better they are nourished, and the more they multiply. 

 The plant sends out rootlets in all directions ; those 

 which come in contact with food, live, enlarge, and ram- 

 ify ; those which find no nourishment, remain undevel- 

 oped or perish. 



The Quantity of Roots actually belonging to any Plant 

 is usually far greater than can be -estimated by roughly 

 lifting them from the soil. To extricate the roots of 

 wheat or clover, for example, from the earth, completely, 

 is a matter of extreme difficulty. Schubart was the first 



