Well, I just pulled out my copy of "Savage Garden" by Peter D'Amato because I remembered him discussing various climatic forms of D. intermedia. He does cover them on a few different pages and it's too much to copy it all here. (pp 134, 135, 137 and 142). A few quotes however; "The temperate forms...most often grow semi-aquatically around lakes in pure peat covered in a few inches of water. The plants will for stems several inches high with small, spoon shaped leaves on narrow petoiles with
WHITE flowers." - "Tropical forms, such as those from Cuba, have smaller compact rosettes perfect for terrariums. Very large forms are often found in New Jersey, the Carolinas and Gulf States. I like to grow these in undrained bowls of waterlogged peat moss." - Other notes that I won't quote in their entirety; those originating in Wisconsin are cold-temperate and may experience dormancy lasting 6-7 months and can survive temps well below zero degrees. From Louisiana - warm temperate-dormant 3-4 mos.- can handle light frost or brief freezing. Cuba - no dormancy- can not handle freezing.
Later he says, "If you live in a warmer climate, you can always remove the hibernaculum once the plant dies down, and refrigerate it in an air-tight, plastic bag with a few strands of damp sphagnum moss. When dormant, these plants usually lose their roots as well as leaves."
Sorry, this probably won't help with ID'ing them but I hope it might be useful anyway!
Shawn