Dieffenbachia are lovely houseplants, I've grown a few of them over the years and the variegations in foliage is really pretty.
I don't know about rare varieties of Dieffenbachia's but the big box stores (Lowes, Home Depot, Wal-Mart) get most of their plants from large wholesale nurseries located in South Florida where they are mass produced. If you can post a photo of your plant someone might be able to identify the cultivar and give you a name. You can also check those listed in our database to see if you find a match:
http://garden.org/plants/brows...
