of the leaf-stalk, as in the Lupine,
the Common Clover, the Virginia Creeper (Fig. 93), and the
Horse-chestnut and Buckeye (Fig. 159). They evidently answer to the
_radiate-veined_ or _palmately-veined_ simple leaf. That is, the
Clover-leaf of three leaflets is the same as a palmately three-ribbed
leaf cut into three separate leaflets. And such a simple five-lobed leaf
as that of the Sugar Maple, if more cut, so as to separate the parts,
would produce a palmate leaf of five leaflets, like that of the
Horse-chestnut or Buckeye.

152. Either sort of compound leaf may have any number of leaflets; yet
palmate leaves cannot well have a great many, since they are all crowded
together on the end of the main leaf-stalk. Some Lupines have nine or
eleven; the Horse-chestnut has seven, the Sweet Buckeye more commonly
five, the Clover three. A pinnate leaf often has only seven or five
leaflets, or only three, as in Beans of the genus Phaseolus, etc.; in
some rarer cases only two; in the Orange and Lemon and also in the
common Barberry there is only one! The joint at the place where the
leaflet is united with the petiole distinguishes this last case from a
simple leaf. In other species of these genera the lateral leaflets also
are present.

153. The leaflets of a compound leaf may be either _entire_ (as in Fig.
126-128), or _serrate_, or lobed, cleft, parted, etc.; in fact, may
present all the variations of simple leaves, and the same terms equally
apply to them.

154. When the division is carried so far as to separate what would be
one leaflet into two, three, or several, the leaf becomes _doubly_ or
_twice compound_, either _pinnately_ or _palmately_, as the case may be.
For example, while the clustered leaves of the Honey-Locust are _simply
pinnate_, that is, _once pinnate_, those on new shoots are _bipinnate_,
or _twice pinnate_, as in Fig. 160. When these leaflets are again
divided in the same way, the leaf becomes _thrice pinnate_, or
_tripinnate_, as in many Acacias. The first divisions are called
_Pinnae_; the others, _Pinnules_; and the last, or little blades
themselves, _Leaflets_.

[Illustration: Fig. 160. A twice-pinnate (abruptly) leaf of the
Honey-Locust.]

155. So the palmate leaf, if again compounded in the same way, becomes
_twice palmate_, or, as we say when the divisions are in threes, _twice
ternate_ (in Latin form _biternate_); if a third time compounded,
_thrice ternate_ or _triternate_. But if the divi