Finally this fall I have a useful way to confirm the identity of the many Colchicum species I've raised from seed over the years. "Colchicum: The complete guide," by Christopher Grey-Wilson, Rod Leeds, & Robert Rolfe, Royal Horticultural Society (2020), is a big, expensive volume. It may not be the last word on this still problematic genus, but it helps. The elaborate keys are easy to use; if you don't know the lexicon, there is a glossary in the back matter. Once you've spotted possibilities, you have to read the individual entries to see exactly how similar species are being distinguished. There are good color photos for most species, which give you a sense of the general habit of the plant. So far I've identified a stray one that got into the rock garden as C. baytopiorum, and one grown from seed as C. peloponnesiacum is almost certainly C. troodii. One that had lost its label when I lifted part of the bulb house this summer is definitely C. stevenii, which I knew I had somewhere. Some others seem to be true to name. It's not too hard to look at colchicums in flower because almost all the diagnostic parts are above ground.