I saw this thread and your pictures remind me of a couple of dieffenbachias that I have here in the Yucatan. They are common, I'm sorry but I don't know the name either. Some of them have lighter leaves and some are very dark green. I have one of each but they are not prime specimens as they are on a terrace that gets dim light in the summer so they are not looking good right now. I'm afraid that they also get forgotten fairly often when I'm watering. Here are a couple pics
This is the light green one, the newer leaves at the bottom seem to be doing ok but the original stalk is looking a bit dried out or light deficient.
the whole plant
This is the darker green version, I've had this one a lot longer and while it is showing the effects of less sun from the summer, it is used to it or doesn't need as much light.
It's not easy to get latin names of plants here, there is one nursery whose owners are very knowledgeable and who generally can get me a true name. I will ask them about these plants the next time I'm there. I'm fairly certain they are dieffenbachia of some sort due to the cane like trunk.
