In article , Iris Cohen
writes
It seems that the DNA data places Celtis and allies, hence Celtidacee, as
distinct from Ulmaceae,

Who are these allies?

Additional genera mentioned as being placed in Celtidaceae include
Lozanella, Trema and Aphananthe. Judd et al (1st edn) says that
Celtidaceae has 9 genera; other possibilities are Gironneira and perhaps
Pteroceltis (APweb has this as near to Humulus and Cannabis).
--
Stewart Robert Hinsley