Folding Leaves at Night, Cool!
I've got several Cassia Alata or also called Senna Alata, seedlings going and they do a marvelous thing at night ... their leaves fold up!
It kind of reminds me of what Mimosa Pudica ( The Shy Plant ) does, but Cassia Alata's leaves don't fold when you touch them.
You can actually watch them fold however if you are patient at dusk.
This is a very interesting and easy to germinate plant that grows shrub height and produces many candelabra like yellow flowers ( also know colloquially as the candelabra plant ).