This is my journey learning to garden. It will contain the things I did right and wrong while turning my yard into an earthly paradise.
There's nothing odd about your plant at all. This is a normal occurrence. It's what makes the group of plants known as Calatheas, otherwise known as Prayer Plants, so interesting. I have a few of them out in the shadehouse and whenever it's overcast and dull, or about sunset time they all close up their leaves like they're saying their goodnight prayers!
I second what Bernie said :)
Thank you for visiting my blog One A Day In The Garden - I am happy to have gardening friends. Your house plant is in beautiful form. I don't have one of those but I've had some other plants that close up at night and in the darker days, tis normal for them.
Plants in Action has a chapter that discusses the mechanisms behind different nastic responses in plants, including the nocturnal leaf-folding of the Marantaceae family.(I've reached your weblog through Danger Garden, and I'm simultaneously daunted by and envious of the wonderfully thorough, systematic and cerebral way you approach gardening. I'm partial to weblogs such as yours that provide just as much text as they do photographs. it's a real treat reading through your recent posts. Kudos!)