100: ESSENTIALS OF BOTANY 
Compare the mode of veining or venation of the elm and the 
maple leaf by making a diagram of each. 
These leaves agree in being netted-veined, i.e., in having veinlets 
that join each other at many angles, so as to form a sort of delicate 
lace-work, like Figs. 59 and 60. 
They differ, however, in the arrange- 
ment of the principal veins. Such a leaf 
as that of the elm is said to be feather- 
veined, or pinnately veined. 
The maple leaf, or any leaf with closely 
similar venation, is said to be palmately 
veined. Describe the difference between 
the two plans of venation. 
117. Relation of Venation to 
Shape of Leaves. — As soon as the 
student begins 
to observe leaves 
somewhat 
widely,- he can ro 
hardly fail to 
notice that there 
is a general rela- 
tion between the 
plan of venation and the shape of the 
leaf. How may this relation be stated? 
In most cases the principal veins follow 
at the outset a pretty straight course, a 
fact for which the student ought to be 
able to give a reason after he has per- 
formed Exp. XVI. 
On the whole, the arrangement of the _ F16- 68. Leaf of 
veins seems to be such as to stiffen ae bib cies 
the leaf most- in the parts that need most support, and to 
teach the region near the margin by as short a course as 
ib \ 
Fic. 62. Palmately Divided 
Leaf of Buttercup. 
