I have a plant that came with a house we bought. It looks like a giant onion, with a hardball sized bulb and it only has grown huge vertical leaves (about 2 to 2 1/2 feet) that are almost solid green and whiter at the base by the bulb. One leaf will grow straight up, and when it becomes too large, it slumps over and will die. Usually there is always one dying and a little one sprouting. I have never seen a flower on it and all it does is just grow the leaves. People have said it is a Christmas plant and we need to put it in a dark room, but after looking up Christmas plants, I didn't really see anything like ours. Any ideas? Thanks for your help.