The studies in the behavior of plants have made remarkable progress during the century, and this also derives much aid from morphology. The strawberry sends out runners from which new plants are formed; but, tiring of this, eventually sends the runner upward to act as a flower stalk. What might have been but a bunch of leaves and roots at the end of the runner is now converted into a mass of flowers and pedicels at the end of a common peduncle. In some cases Nature reverses this plan. After starting the structure as an erect fruit-bearing stem, it sends it back to pierce the ground as a root should do. This is well illustrated by the peanut. In the common _Yucca_, the more tropical species have erect stems; but in the form known in gardens as Adam’s needle and thread—_Yucca filamentosa_—the erect stem is sent down under the surface of the ground, and is then a rhizome, instead of a caudex, or stem. [Illustration: PEANUT. A pod magnified.] Modification in connection with behavior is further illustrated by the grapevine and Virginia creeper. The whole leading shoot is here pushed aside by the development of a bud at the base of the leaf, that takes the place of a leading shoot. The original leader then becomes a tendril, and serves in the economy of the plant by clinging to trees or rocks, or in coiling around other plants in support. Great progress has been made in this department of botany within recent years. Darwin has shown that the tendrils of some plants continue in motion for some time in order to find something to cling to. The grapevine especially spends a long time in this labor if there is difficulty in reaching a host. The plant preserves vital power all this time, but no sooner is support found, than nutrition is cut off, and the tendril dies, though, hard and wiry, it serves its parent plant as a support better dead than alive. The amount of nutrition spent in sustaining motion is found to be enormous. A vine that can find ready means of support grows with a much more healthy vigor than one that has difficulty in finding it. Many plants present illustrations.