Arum rupicola var. virescens also generates heat when it blooms. They bloom in the evening, usually around the end of april, with a nice manure smell and when you put your nose up to them a shocking burst of warmth. I couldn't find a photo of my plants, but here is one off the web: http://hillkeep.ca/images/… Hi Ellen- Another neat fact about them is that they will generate their own heat to push up through the snow. They are native here in IL too. I was too busy to see if this fact is true- we had late enough snow.