34: THE WHEAT CULTUKI6T. 



" Each of these root hairs or suckers consists of a sub- 

 cuticular cellule of the epidermis, more or less length- 

 ened out into a cylindrical hair-like form. It is at first 

 uniformly smooth and straight, but at a later period 

 either the extremity or the upper portion or sometimes 

 nearly the whole length becomes variously deformed by 

 club-shaped dilations, or irregular ramifications. The 

 length of the suckers, and the shapes of these irregu- 

 larities, are often more or less affected by the obstacles 

 they meet with in the earth, but not entirely so ; for 

 when grown in water perfectly free from an impediment 

 there is very great irregularity in both respects. In- 

 ternally, however much ramified, the cell remains entire 

 with one continuous cavity from the base to the extrem- 

 ity of all its branches. Its walls also consist of a single 

 membrane, no chemical reagent having disclosed any 

 distinction between the walls of the cell and an external 

 cuticle. 



" These suckers appear to absorb the alimentary juices 

 by endosmose over their whole surface. Like leaves on 

 the young aerial shoots, they are formed on the young 

 shoots of the roots ; like leaves also they die and disap- 

 pear after a longer or shorter season, leaving the old 

 roots entirely without them. 



" When fully formed, and before they decay, these 

 suckers become more or less covered in their irregular 

 branching portion (rarely in their basal cylindrical part), 

 with viscous papillae or adhesive globules, forming gran- 

 ular masses, to which the surrounding earthy particles 

 strongly adhere. Are these viscous masses excretions 

 from the roots, or are they the residue of substances 

 contained in the earth and chemically decomposed by 

 the roots in the absorption of such elements only as 



