From Janis Ruksans "Crocuses a complete guide to the Genus":
Crocus kosaninii (2n=14) is a newer species named in honor of the famous Yugoslavian botanist Nedeljko Kosanin who described C. pelistericus and C. scardicus. It grows in lowland oak forest and mixed scrub within a limited area in Southern Serbia"

It is an excellent naturalizer in Oregon, I guess since a lot of our habitat here is often Lowland oak forest and scrub.