Riddle me this.
I bloom when taken into sunlight or rain, but fade when taken into shadow.
What am I?
First, I gone through a list of flowers, but I could not find such flower. Moreover, I do not think it is a flower.
Any ideas, what is it?
I guess you are an:
Umbrella
Because:
It "blooms" (is opened up) to shield from sunlight or rain, but can be closed when in a shadow.
You could be a
rainbow. You can see it when it rains or in the sunlight, it blooms in a lot of colors, but dies in the shadow.
I know this is not what you expected, so I'll disappoint you - you're a plant indeed: most probably a Mimosa pudica, because that triples the sense of the word "bloom".
Most of the plants that bloom before late autumn or winter (M.P. included) require an amount of direct sunlight and rain to be able to bloom; if kept in low-light state (shadow) the flowers usually won't form (the plant won't bloom), as the plant still "believes" it's too early for it. OTOH, the plant is an annual, meaning it actually "fades" in "shadow", i.e. usually dies as soon as the amount of light it gets decreases heavily (late autumn). Also, a M.P seed also fits - it "blooms" (opens up) if it gets enough sunlight and rain. If kept dry and in shadow, it simply won't germinate.
That being said, the real trick is that M.P. really "blooms" (leaves open up and flowers uncurl, similarly to the aforementioned umbrella) if the plant receives enough light and after rain (in case of direct rain, it closes the leaves when the drops hit them, but reopens them and "blooms" shortly thereafter) - the leaves curl when there's no rain for a long time, so a dried-out plant, when taken into rain, will "bloom" in a matter of minutes. OTOH, the leaves routinely open and close ("bloom" and "fade") based on daily solar cycle, i.e. the plant "blooms" in the morning due to sunlight, and "fades" (quite visibly, so to speak) as soon as the sun goes down (or simply if you put it in deep shadow).
FWIW, I've noticed (and even have a video recording of) other plants (e.g. of Atropa genus) that show the very same mechanism, albeit more slowly - they curl their leaves when left dry and "fade" (close their flowers, curl their leaves, finally "fade" in the sense of plant death) when kept in deep shadow for too long. OTOH, when a dried-out and light-deprived plant finally gets light and water, it gradually "blooms" (uncurl the leaves, open the flowers) usually within an hour or two.
Reference: own experience with M.P. and other plants; also see e.g. https://www.youtube.com/watch?v=2kSlK8GdLPI, https://www.youtube.com/watch?v=Fl-3lpYXnYg or simply CYLOB.