⚠ Version 1.1 of The Plant List has been superseded and should no longer be used.
The new version is available at http://www.worldfloraonline.org. The new version is enhanced, using more data sources including Taxonomic Expert Networks and will be more frequently updated.
Full publication details for this name can be found in IPNI:
This name record (from RJP) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Crataegus williamsii in version 1 of The Plant List.