ex of leaves.]

138. =As to degree and nature of Division=, there is first of all the
difference between

_Simple Leaves_, those in which the blade is of one piece, however much
it may be cut up, and

_Compound Leaves_, those in which the blade consists of two or more
separate pieces, upon a common leaf-stalk or support. Yet between these
two kinds every intermediate gradation is to be met with.

[Illustration: Fig. 142-147. Kinds of margin of leaves.]

139. =As to Particular Outlines of Simple Leaves= (and the same applies
to their separate parts), they are

_Entire_, when their general outline is completely filled out, so that
the margin is an even line, without teeth or notches.

_Serrate_, or _Saw-toothed_, when the margin only is cut into sharp
teeth, like those of a saw, and pointing forwards; as in Fig. 142.

_Dentate_, or _Toothed_, when such teeth point outwards, instead of
forwards; as in Fig. 143.

_Crenate_, or _Scalloped_, when the teeth are broad and rounded; as in
Fig. 144.

_Repand_, _Undulate_, or _Wavy_, when the margin of the leaf forms a
wavy line, bending slightly inwards and outwards in succession; as in
Fig. 145.

_Sinuate_, when the margin is more strongly sinuous or turned inwards
and outwards; as in Fig. 146.

_Incised_, _Cut_, or _Jagged_, when the margin is cut into sharp, deep,
and irregular teeth or incisions; as in Fig. 147.

_Lobed_, when deeply cut. Then the pieces are in a general way called
LOBES. The number of the lobes is briefly expressed by the phrase
_two-lobed_, _three-lobed_, _five-lobed_, _many-lobed_, etc., as the
case may be.

140. When the depth and character of the lobing needs to be more
particularly specified, the following terms are employed, viz.:--

_Lobed_, in a special sense, when the incisions do not extend deeper
than about half-way between the margin and the centre of the blade, if
so far, and are more or less rounded; as in the leaves of the Post-Oak,
Fig. 148, and the Hepatica, Fig. 152.

_Cleft_, when the incisions extend half way down or more, and especially
when they are sharp; as in Fig. 149, 153. And the phrases _two-cleft_,
or, in the Latin form, _bifid_, _three-cleft_ or _trifid_, _four-cleft_
or _quadrifid_, _five-cleft_ or _quinquefid_, etc., or _many-cleft_, in
the Latin form, _multifid_,--express the number of the _Segments_, or
portions.

_Parted_, when the incisions are still deeper, but yet do not quite
reach to the midrib or