Chameleon vine, Boquila trifoliata
The chameleon vine is climbing plant of the temperate rainforests of southern Chile. At first glance it is not a very remarkable creeper but on closer inspection it turns out to have most unexpected abilities which are not at all understood at present. Somehow it is able to change it leaf shape and appearance to match the plants it is climbing over. In some cases this apparent mimicry is not very convincing, in others the similarity between the unrelated model and the mimic is striking. What is even more bizarre is that one vine can produce different leaf forms as it creeps over several different plants.
How it does this is a complete mystery. Expression of different genes modulated by transcription factors presumably explains the different leaf shapes and sizes, and the prominence of veins. How the chameleon vine detects the leaf shape of the model plant is the big mystery. There has been a suggestion that plants somehow 'see' what is around them, but this is not very convincing. It is more likely that certain proteins produce distinct leaf characteristics in all plants and that the chameleon vine is exceptionally sensitive to these, but any such proteins have not been identified.
Although the mechanism producing mimicry is unknown, the benefits are clear. Experiments have shown that mimic leaves are rarely attacked by herbivores, whereas non-mimic leaves have high levels of damage.
Source: Gianoli, E. & F. Carrasco-Urra. 2014. Leaf mimicry in a climbing plant protects against herbivory. Current Biology 24(9): 984-987 [http://dx/doi.org/10.1016/j.cub.2014.03.010]
Photo from Gianoli & Carrasco-Urra 2014