ABSORPTION OF WATER. 



47 



plants are thin-walled, unicellular, unbranched filaments, 

 which are developed from the epidermal cells of the root 

 at . some little distance behind its growing-point ; they are 

 of short duration, and leave after their death no trace of their 

 existence. In many of the lower plants the root-hairs are 

 multicellular and branched, and in the Muscineae the cell- 

 wall is frequently thickened and of a brown colour. 



The plants which we shall more especially consider are 

 land-plants, plants, that is, which have their roots imbedded 

 in the soil. It will therefore be advantageous to give here a 



FIG. 10. 



FIG. ii. 



FIG. 10 (after Sachs). Seedling of Sinapis alba: A, after removal from the soil ; 

 B, after washing in water. 



FIG. ii (after Sachs). Ends of root-hairs of a seedling of Triticum vulgare, 

 shewing their intimate connexion with particles of soil. 



