tendril, coiling, clasping organ that enables the stems of plants to climb (see wild vines). In many plants, these organs are modifications of stems, leaves, or leaflets, but in the grapevine they are modified inflorescences, developing at two of every three consecutive nodes. Tendrils are sensitive to touch (thigmotropic); when sufficiently elongated, they react to pressure on their surface by coiling around the touched object, be it a wire, a part of the vine, or any other adjacent material. Once coiled, the tendrils become lignified, very tough, and difficult to remove.
