OUTLINE OF STRUCTURAL BOTANY 15 
petiole is not a branch or twig of the tree from which five leaves 
might arise, for when the leaf is ripe in autumn this common 
petiole looses its hold upon the stem and it and its five blades fall 
to the ground together. The petiole and the five blades then con- 
stitute a single leaf and the five blades are not five leaves, but so 
many leaflets of a compound leaf. Another example of compound 
leaf is found in that of the locust tree, where the petiole proceeds 
as a main stem, on each side of which is a series of oval or rounded 
leaflets, the petiole terminating as the midvein of an odd leaflet. 
These rounded blades are no more separate leaves than are the 
radiating blades of the horse-chestnut, but are elements of the 
compound leaf. In the case of the radiating leaflets the arrange- 
ment is known as a palmately compound leaf ; while in the case 
where the secondary petioles branch from the main leaf-stalk like 
the barbs of a feather it is a pinnately compound leaf. Hence it 
will be seen that similar terms are used both for the simple and 
compound leaf and this is a fact which the amateur should not 
fail to comprehend, that while the terms of science may not be 
familiar the true scientist employs the least number of new terms 
that it is possible to use in the necessary description and classifica- 
tion of his object. 
We find many other examples of compound leaves, as in the 
clover with its three leaflets, most of the potentillas with their 
palmate five leaflets and many species of the pea family, with their 
pinnate double rows of leaflets. 
STIPULES 
At the base of the leaf-stalk or of the blade of many leaves are 
found leaf-like appendages having often the color and general 
character of a leaf but differing usually in form and size from the 
leaf itself. Such appendages are found at the foot of the petiole 
of a rose leaf, where, starting from the very base of the petiole it 
extends along its column as a sort of fringed collar. 
The stipules constitute a very important feature of the leaf from 
the point of view of the determination of different species, for a 
great many leaves are without stipules, while some have very con- 
spicuous ones. About the bud of the magnolia two large brown 
stipules form a thick protecting cover, which falls as the leaf ex- 
