What got me started was the article I cited in my Trout Lily post, in particular, this passage:
The designation spring ephemeral has at times been applied erroneously to other early-blooming woodland herbs such as bloodroot, Jack-in-the-pulpit, wild ginger, hepatica, woods phlox, and various species of trillium. But these species don’t qualify for the ephemeral guild because they retain leaves and ripen fruit well after the leaf canopy closes. Slender fumewort (Corydalis micrantha) has also been cited as a spring ephemeral, but the plant doesn’t qualify since it normally grows on sandy roadsides and in fields or waste places where its life cycle is not correlated with a woodland canopy sequence. (George Ellison, Spring Ephemerals: Strategies Reconsidered, Notes of the Pennsylvania Native Plant Society, Jan-Mar 2007 edition: Source)
Perhaps I’ll simply put two sections in my next book: True Ephemerals and Other Spring Flowers. Then I can include some of my other favorites of the deciduous woods!