Does anyone know if a book or list exists in which one can look up whether a species of plant makes nectar or not? I am part of a study of butterfly habitat at the Indiana Dunes, and we are trying to survey nectar sources. However, I think some of plants we are listing do no really make nectar. e.g., I suspect that roses and Tradescantia don't make nectar, but goldenrods and Cynthia do. It would be helpful to be able to check this in a book somewhere, since most of the plants aren't in bloom. Any ideas? Liz Day University of Illinois at Chicago [log in to unmask]