Vines have a slender, flexible trunk that is mostly made up of water conducting tissues. The vines borrow the strong woody trunks of the forest trees to support the weight of their leaves and stems. To hitch a free ride to the sun the vines have a number of adaptations for climbing. Most people know about the tendrils on grapes, pumpkins or passionfruit vines. The same tendrils that allow chokos to climb over a country dunny can be found on rainforest plants but there are many other climbing mechanisms used by rainforest vines.
Tendrils are usually modified leaves, branching like the veins of a normal leaf.
Some rainforest vines, for example Bull cane, have a different kind of tendril that is an extension of the mid vein of the leaf producing a leaf-tip tendril. These look rather like a coiled watch spring. Far from the sunlight at the top of the forest canopy, all the vines begin life in a conventional way, either as a seedling germinating in the soil or as a sucker from the stems or roots of an existing vine. Many are able to survive in low light conditions until they become established and attached to a host tree. Once in contact with their host they begin their upward climb toward the sunlit canopy.