Kevin, the parentage of modern Asiatic hybrids is pretty complicated. Here is a list of a few of the many species that have been involved over the years:

L. maculatum
L. dauricum
L. bulbiferum
L. davidii
L. lancifolium
L. umbellatum
L. amabile luteum
L. cernuum
L. concolor
L. pumilum
L. callosum
L. wardii
L. lankongense

Might I suggest you get a copy of The Gardener's Guide to Growing Lilies published by Timber Press or another well regarded monograph on the genus? This should provide some background and discuss these rather uncommon (in today's garden) species in greater detail. Good luck with your research!

Thank you so much, gardengal48! I'll look for that book, and maybe do some web searches on their points of origin, and see if that brings me any insights. Will post if I find anything earthshaking! : ]) Feel free to blow raspberries if it's only earthshaking to me.

Kevin : )