Hi David, I have no expertise with Trillium. I agree it is confusing. I looked at CalFlora for T. chloropetalum http://calflora.org/cgi-bin/species_query.cgi/… and for T. angustipetalum http://calflora.org/cgi-bin/species_query.cgi/… and I looked on google maps for where Redwood National Park overlaps with the distribution maps on the CalFlora pages. Looking at the 'Distribution Grid' more detailed view, I see T. chloropetalum is more coastal and T. angustipetalum more montane. Based on those items alone, I would have concluded T. chloropetalum could be found in Redwood National Park, as well as T. angustipetalum. So I expect CalFlora is just not as up to date as some other resource. Perhaps the answer is that a photograph and a map are not sufficient for ID? - Gastil