sion goes still
further, or if the degree is variable, we simply say that the leaf is
_decompound_; either palmately or pinnately decompound, as the case may
be. Thus, Fig. 161 represents a four times ternately compound (in other
words a _ternately decompound_) leaf of a common Meadow Rue.

[Illustration: Fig. 161. Ternately decompound leaf of Meadow Rue.]

156. When the botanist, in describing leaves, wishes to express the
number of the leaflets, he may use terms like these:--

_Unifoliolate_, for a compound leaf of a single leaflet; from the Latin
_unum_, one, and _foliolum_, leaflet.

_Bifoliolate_, of two leaflets, from the Latin _bis_, twice, and
_foliolum_, leaflet.

_Trifoliolate_ (or _ternate_), of three leaflets, as the Clover; and so
on.

_Palmately bifoliolate_, _trifoliolate_, _quadrifoliolate_,
_plurifoliolate_ (of several leaflets), etc.: or else

_Pinnately bi-_, _tri-_, _quadri-_, or _plurifoliolate_ (that is, of
two, three, four, five, or several leaflets), as the case may be: these
are terse ways of denoting in single phrases both the number of leaflets
and the kind of compounding.

157. Of foliage-leaves having certain peculiarities in structure, the
following may be noted:--

158. =Perfoliate Leaves.= In these the stem that bears them seems to
run through the blade of the leaf, more or less above its base. A common
Bellwort (Uvularia perfoliata, Fig. 162) is a familiar illustration. The
lower and earlier leaves show it distinctly. Later, the plant is apt to
produce some leaves merely clasping the stem by the sessile and
heart-shaped base, and the latest may be merely sessile. So the series
explains the peculiarity: in the formation of the leaf the bases,
meeting around the stem, grow together there.

[Illustration: Fig. 162. A summer branch of Uvularia perfoliata; lower
leaves perfoliate, upper cordate-clasping, uppermost simply sessile.]

[Illustration: Fig. 163. Branch of a Honeysuckle, with
connate-perfoliate leaves.]

159. =Connate-perfoliate.= Such are the upper leaves of true
Honeysuckles. Here (Fig. 163) of the opposite and sessile leaves, some
pairs, especially the uppermost, in the course of their formation unite
around the stem, which thus seems to run through the disk formed by
their union.

[Illustration: Fig. 164. Rootstock and equitant leaves of Iris. 165. A
section across the cluster of leaves at the bottom, showing the
equitation.]

160. =Equitant Leaves.= While ord