I.I:. I IKS 119 



sprinjj^, when a fine line ov lid^c may be traced 

 just below the junction of the leaf with the stem. 

 This (lark line is in realitv a thin la)-er of cork, 

 which, (luiini; the summer months, continues to 

 ^row inwards t(^ torm in due time a co\erin<^ 

 for the bare place on the stem that will be left 

 when the leaf falls off; this is called the leaf- 

 scar. 



It is interestiiiL;' to watch this line, i;"rowin^ m<jre 

 and more \isible as the year ^(jcs on. 



Another curious fact is, that some of the starch 

 which the lea\es have been makinj; durin^i^ the 

 summer, becomes stored uj:) in autumn at the base 

 of the leaf-stalk, so as to afford nourishment to the 

 bud which will arise out (jf the axil of the leaf. 

 \\ hen a weak solution of iodine is appHed to it, 

 this starch turns blue, and in this way its presence 

 can be ascertained. 



The fall of the leaf a{)}jears to take place mainl\' 

 because the starch lias the effect of softening; the 

 cells of the leaf-stalk ; as it dries up it loses its 

 hold of the twi^, and either the wind or a sliLjht 

 frost will suffice to brin^" the leaves dcjwn U) the 

 ground in showers. 



