And so it is with tendrils. In certain plants the point of the leaf, through ages of "natural selection," has gradually been prolonged into a slender arm, which clasps the branches of trees, and enables the plant thus endowed to climb higher to sun and sky, and thus to thrive more vigorously than its less fortunate brothers. The plant so advantageously equipped transmits its tendency to its offspring, and has therefore survived in place of its ancient fellows, and is the type perpetuated or "selected" by nature. Such a tendril, then, is a modified leaf. How is it in the pea? Here we find four leaflets in two opposite pairs, but _no odd leaflet_ at the end of the main stalk, such as we see in almost all other plants of its family. But in place of this leaflet we find a branching tendril reaching out on all sides for conquest. How quietly by the aid of these eager arms the sweet-pea climbs to the top of its brush! In the common catbrier or smilax we see two slender thread-like tendrils growing from the base of each leaf. Here we have another modification, a development of the "stipule," that tiny pointed growth common to many leaves, and particularly notable at the base of a rose leaf. Still another plan has been evolved in the grape-vine. If we examine our grape arbor in June we find a number of drooping, swaying branches. The leaves are scattered singly at intervals of a few inches along the branch, each of the upper ones being attended on its opposite side by a drooping cluster of mignonette-scented blossoms. Thus they follow down towards the tip of the branch, where the clusters suddenly cease, and are replaced by long, slender, curving and branched tendrils, sometimes ten inches long. We might thus reasonably assume the tendril in this case to be a modified blossom cluster, but there is no need for us ever to assume such a thing. If we will only search with sufficient care we shall at last discover the absolute proof of the fact in a tendril which is partly in blossom, the nearest leaf-joint above it having a full cluster of blossoms, and the tendril below it, nearer the tip, not a few scattered flower-buds at its tips. This grape-vine instance may be taken as a demonstration that in no case is the tendril a special or primal organ, but merely an old one adapted to a new purpose. In one instance from a leaf, in another from a flower-stalk, just which can generally be determined by a sufficient search for the telltale _intermediate form_ somewhere to be found on the plant.