WHITE CLOVER 



123 



conveniently effected by the long leaf-stalk, and by an 

 organ of movement at its base. A very slight change of 

 figure at the base, acting upon the long lever of the leaf- 

 stalk, causes a visible displacement of the leaf -blade. 

 With most grasses, on the other hand, the great object is 

 to gain a moderate height rapidly. They have telescopic 

 haulms, and long narrow leaves springing at different 

 heights, out of one another's way. 



The base of a clover-leaf bears a pair of stipules, which 



FIG. 31. Prostrate stem of white clover, with leaf-bases, 

 stipules and leaf-buds. A leaf in the sleep-position is intro- 

 duced behind. Natural size. 



form a protective sheath (Fig. 31), often enclosing the 

 rudiments of a young branch or root, besides the organ 

 of movement of the leaf-stalk. The delicate tissues are 

 thus screened from intense light and heat, and in some 

 measure protected from trampling by cattle. Towards 

 the tip of a growing branch the leaves become crowded, 

 and one sheath often encloses others, thus giving addi- 

 tional protection to the tender growing-point. 



Each of the leaflets of the trefoil leaf bears a whitish 

 patch near the middle of its upper surface. I wish I could 

 tell you what is the use of this patch. All that I know is 



