A tendril is a modified part of the shoot. Tendrils provide support by growing around nearby structures. Tendrils grow tightly around the wires of trellis systems providing strong support to the growing vine.

At left is a more magnified image of the primary tissues of the tendril. The epidermis is composed of epidermal cells, the pith and cortex are composed of parenchyma cells, and primary xylem and primary phloem tissues make up the primary vascular bundles.