Concepts of "seeing plants" have been rather ignored in the early 20th century, but research suggests they may actually exist.

This means trees and other plants, down to the simplest microorganism, may have some way of observing us. This suggests that plants may be capable of vision, and may even possess something like an eye, though a simple one at best.

According to Scientific American, the idea that plants may have "eyes" is nothing new. In 1907, Charles Darwin's son Francis hypothesized that leaves may have organs that are a combination of lens-like and light-sensitive cells. Experiments conducted in the early 20th century also suggests and confirms such structures.

These are now called ocelli, and they do exist. However, the concept of a "seeing plant" fell off - only to reemerge in the past few years.

Frantisek Baluska, a plant cell biologist at the University of Florence in Italy, laid out new evidence that vegetables may be visually aware. In the recent issues of Trends in Plant Science, as detaild in Research Gate, his team pointed out that the 2016 discovery of the Synechocystis cynanobacteria's true nature is key.

It acts like ocelli, and they are single-celled organisms capable of photosynthesis. They said these cyanobacteria use the entire cell body as a lens to focus an image of the light source at the cell membrane akin to the retina of an animal eye.

Though they are not yet sure as to what the purpose of this mechanism is, its existence suggests that a similar one could have evolved in higher plants.If something like this is already present at the lower level of evolution, this may be kept.

Recent work also shows that plants such as the cabbage and mustard relative Arabidopsis make pro teins that are involved in the development of functioning eyespots, which are the ultrabasic eyes found in single-celled organisms like green algae.

Other research reveals plants have visual capabilities we do not understand yet. For instance in 2014, climbing wood vine Boquila trifoliolata can modify its leaves to mimic the colors and shapes of its host plant.