62 



OUTLINES OF PLANT LIFE. 



Only in rare cases are they wanting. They live for a 

 shorter or longer time, but are always, as compared with the 

 duration of the root, quite, transient. The older part of the 

 root, therefore, is without root-hairs because of their death. 



^v 



Fig. 51. — Transverse section of a young root grown in soil, showing root-liairs with 

 adherent soii-particles, the cortex, and the stele. Magnified about 20 diam. — After 

 Frank. 



The youngest part of the root is likewise free from them, 

 because they have not yet been produced. As the root 

 grows in length, new root-hairs are continually being pro- 



