Vespertine is a term used in the life sciences to indicate something of, relating to, or occurring in the evening. In botany, a vespertine flower is one that opens or blooms in the evening. In zoology, the term is used for a creature that becomes active at dusk.

https://en.wikipedia.org/wiki/Vespertine_(biology)#:~:text=Vespertine%20is%20a%20term%20used,such%20as%20bats%20and%20owls.

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