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