http://www.plantsoftheworldonline.org/taxon/urn:lsid:ipni.org:names:317401-2#synonyms

http://www.catalogueoflife.org/col/details/species/id/247d40b5383e35252aaafc38b9fbb67a

http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250101928

https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=24430#null

There are many synonymes of Philadelphus lewisii that are still active on iNaturalist and make this genus very confusing. Only 3 observations have ever been made with one of these synonymes (Philadelphus lewisii ellipticus) and 2 with the name Philadelphus lewisii lewisii.