10 



THE ECOLOGICAL RELATIONS OF ROOTS. 



This plant has a root system which spreads immediately below the sm-face. 

 Many of the numerous small roots pursue an oblique direction and spread 

 from 12 to 18 inches on either side of the plant before they turn downward. 

 Most of the roots are only about 1 mm. in diameter and poorly branched. 



Fig. 2. — Root system of Liatris punctata. 



Fig. 3. — Root system oiKulmia glulinosa. 



However, they are very abundant in the first 2 feet of soil, while maximum 

 depths of over 5 feet are attained. They are yellowish-brown in color and have 

 a smooth cortex, except the lower roots, which are silvery white. Only 4 

 plants were examined. 



