14 OUTLINE OF STRUCTURAL BOTANY 
fan-like, as many strong ribs or veins as there are lobes to the leaf, 
and that these radiating veins send out a network of smaller veins. 
If we compare this with the leaf of the elm (Fig. 
18), we see that in the latter a strong rib or vein 
runs from end to end through the center of the leaf, 
while other smaller veins diverge on either side and 
at fairly regular distances, like the barbs of a 
feather. Because, in case of the ranunculus leaf 
and others constructed on a similar plan, the veins 
radiate something like the fingers of the hand when 
spread out, such leaves are said to be palmately 
veined, while in the case of the elm leaf and others 
constructed on the feather plan they are said to be 
pin. Purnately veined or feather veined. 
RiGee Loo — 
nately veined Jf we compare our ranunculus leaf and the elm 
leai of Elm. : : . 
leaf with a leaf from the common plantain which 
grows so freely about country dooryards and in waste places we 
observe that in case of the elm and the buttercup the borders are 
not continuous, one being broken by very deep interruptions, the 
other only by the depth of the sharp teeth. On the other hand, the 
borders of the plantain leaf are continuous. Such a border is said 
to be entire, while the others are interrupted. It is somewhat rare 
to find blades of the palmate or feather-veined leaves with entire 
borders, though the entire border is characteristic of the parallel- 
veined leaf. 
As it is well known, the leaf blade assumes many forms, most of 
which have a resemblance to familiar objects, for example: to the 
outline of an egg; of an arrow-head; of a spatula, etc., and dia- 
grams representing several of these forms are given in the plate 
opposite the table which is to follow. 
Compound Leaves 
The leaf, as we have thus far examined it, has only the three 
elements which were at first mentioned, namely, the blade, the 
petiole and the base. Such a leaf is known as a simple leaf. But 
we often find leaves which are apparently more complex; for exam- 
ple, the leaf of the horse-chestnut is composed of five separate 
blades radiating from a stout common leaf-stalk or petiole. ‘This 
