Jim S., you and I are about the same age I think. I'm of the Rassenkreis generation, too. After posting my original message on this broad topic, I happened to check the wiki entry for cline and noticed that that entry uses a translation of Rassenkreis: ring species. By the way, I was not suggesting that the situation with Lilium canadense and L. grayi should be described as a cline. Cline, as usually understood, does not really describe what can be seen there, where there is a rather abrupt transition zone between one entity with a vast range (L. canadense) and another entity which is highly localized (L. grayi). It's fun to speculate about these things. Is Lilium canadense "capturing" Lilium grayi? Is L. grayi infiltrating L. canadense? There is definitely something going on between them. Jim, your description of the situation "a localized intergradation between two young, mostly allopatric and closely related species" is about the way I would describe it - but I would omit the words "species" and "young". Why? Aren't all sexually reproducing species of equal age? What does it mean to call some young and by implication others old? Hasn't there been an unbroken continuum of parents and progeny from the present back into unimaginably distant time for all sexually reproducing organisms? I don't consider my ancestry to be any younger than that of a turtle - it's just that mine has not been so conservative and has been a lot less stable and a lot more opportunistic. One other note, this one definitely meant humorously. Lilium grayi is now evidently well protected for most of the threats which it faced in the past (poaching for instance) or potentially faces in the future (site development for instance). But it seems to me that it still faces a real danger which, I'll bet, has not been addressed: what are the protectors of Lilium grayi going to do about the hummingbird problem? It's the hummingbirds which are mixing things up here. Something's got to be done about them. Jim McKenney jimmckenney@jimmckenney.com Montgomery County, Maryland, USA, USDA zone 7 where it's time to get back to potting bulbs (yes, I'm still at it). My Virtual Maryland Garden http://www.jimmckenney.com/ BLOG! http://mcwort.blogspot.com/ Webmaster Potomac Valley Chapter, NARGS Editor PVC Bulletin http://www.pvcnargs.org/ Webmaster Potomac Lily Society http://www.potomaclilysociety.org/