At the moment a popular question in the physics SE community is about night-blooming cereus: this flower blooms at full moon, that is it is capable of making difference between the moonlight and sunlight.
The question has attracted a lot of guesswork, with some people even claiming that the cereus doesn't know about the moon, but simply blooms at night - the blooming at full moon however seems to find experimental confirmation. It is thus more plausible that the flower distingushes between the light intensities of the moonlight and the sunlight, as suggested here.
The closest question that I found in this forum is about flowers open during the daytime and closed at night (or vice versa). I suppose one could construct a more sophisticated model based on the mechanisms described here, but I would appreciate an expert answer.
To restate the question:
How does night-blooming cereus distinguish between moonlight and sunlight?