FOLIAGE AND SCALE LEAVES. 59 
in which the margin is more deeply excavated. Projections, 
whether small, as teeth, or large, as lobes, generally correspond to 
smaller or larger veins. Lobes 
and the like which follow the ( 
latter are therefore arranged 
either pinnately or palmately. 
A distinction is drawn between s ' 
lobed, cleft, and parted leaves, 
respectively, not more than 
half way, half way or more, 
and almost the whole way to 
the midrib or base. In the 
first case, either the lobes or in- 
terspaces are rounded, and in 
the second, sharply cut. Thus 
we get pinnately and palmately 
lobed, cleft, and parted leaves 
(figs. 22 and 23). The lobes 
may be of very unequal size | 
margins varying like those of lobed Leaf of Oak. cleft Leaf of Poppy. 
complete leaves. Secondary lobes are thus produced in many 
cases, and still smaller subdivisions may also occur. Examine in 
this connection the thrice pinnately-parted leaves of the yarrow 
or millefoil (Achzllea). 
In a large number of leaves division actually extends to the 
midrib or base, giving pinnately or palmately-divided forms. The 
lobes are then termed leaflets, and the leaves are compound, as 
opposed to szmple leaves, such as those described up to this point. 
Leaflets may be either sessile or stalked, and their general out- 
line, &c., are described in the same terms as simple leaves. Pin- 
or palmate. Examples of the former condition are seen in elder, 
ash, and rose (¢/. fig. 24). The axis upon which the leaflets are 
borne clearly answers to the midrib of a simple leaf, and cases 
are not infrequent in which the end of a pinnate leaf is not 
completely divided. This may be seen very well in the jessamine. 
The strawberry (fig. 25) and horse-chestnut (fig. 26) furnish 
typical instances of palmate leaves, where the leaflets are attached 
together at the tip of the petiole. Leaflets, like leaves, are often 
attached by means of a joint or articulation, where separation 
readily takes place. This enables us to distinguish between pin- 
nate and palmate leaves with only three leaflets. Compare these 
where the excavations extend, 
and shape (as in potato), their FIG. 22.—Pinnately- FIG. 23.—Pinnately- 
nately and palmately-divided compound leaves are termed pinnate 
structures, for example, in scarlet runner (fig. 29) and clover, 
