240 AUTUMNAL LEAVES. 



slightly curved mid-stem which runs from the base 

 to the sharply-pointed apex. From each mid- vein 

 a series of prominent, parallel branch veins run on 

 each side to the serrated leaf margins, sometimes 

 in opposite pairs and sometimes in alternation 

 the spaces between being almost equal to each 

 other over the greater part of the leaf. Occa- 

 sionally the parallelograms formed by the almost 

 equidistant branch veins are traversed by short 

 veinlets which fork from the latter; and occa- 

 sionally, also, the normal division of each leaflet 

 into two about equal parts by the mid-vein is 

 varied one part being distinctly smaller than 

 the other. 



The veins of leaves are always more prominent 

 on the under sides of their surfaces than on the 

 upper surfaces, and on the reverse of the Horse- 

 Chestnut leaf not only can the mid- veins, and the 

 branch parallel veins, be clearly seen, but the 

 entire ramification can be traced without the aid of 

 a glass. The venation is very elaborate and 

 beautiful, the course of the veinlets, as they cross 

 the parallels of tissue, being rendered particularly 

 prominent by the thickening of the parts of 



