THE LEAF. 
67 
surround the stem ; perfoliate, when the leaf simply 
clasps the stem. 
Margin. — Very few leaves possess an even margin, 
and according to the degree and character of the in- 
cisions or indentations they are described as serrate, 
when the apex of the divisions or teeth is sharp and 
directed forward like the teeth of a saw ; dentate, when 
the divisions project outward ; crenate, when the teeth 
are more or less rounded ; repand, when the margin 
is somewhat wavy ; sinuate, when the wavy character 
is pronounced ; lobed, when the incisions extend not 
more than half-way into the lamina and the sinus (or 
portion cut out) and the lobe are more or less rounded ; 
cleft, when the incisions are still deeper and the sinuses 
and lobes are somewhat acute ; and parted when the 
incisions extend almost to the midrib. 
(e) COMPOUND LEAVES. 
The divisions of a parted leaf may assume the form 
of a simple leaf when the divisions are known as leaf- 
lets and the whole as a compound leaf. The distinction 
between a simple leaf and a leaflet is, that the former 
has a bud in the axil. Compound leaves may be 
divided into pinnately compound or palmately com- 
pound, this distinction depending upon whether the 
leaflets are arranged pinnately or palmately. A num- 
ber of forms of pinnately compound leaves are recog- 
nized, but these will not be considered here. The leaf- 
lets of compound leaves may themselves be divided t 
forming decompound leaves, as in Dicentra and the 
honey locust. The same terms are used for describing 
the form, apex, margin, etc., of the the leaflets of com- 
pound leaves as are used for simple leaves. 
The following outline shows the principal classes of 
simple and compound leaves : 
