If two names for the same plant are published simultaneously (e.g. in the
same journal or the same day), the name selected by the first author to
recognize their synonymy (in our case _D.citrina_, by Cheek, grr...) is the
valid one. It is of no importance if the information which led to the
decision was correct or not. The situation could only be reversed if there
was unambiguous proof for the other name to have been published (at least
one day) earlier.
>...Or perhaps I'm giving Dr. Cheek a bit too much credit...?
No, not in this respect; Cheek's completely right even if his information
was wrong (this is what makes me hit the ceiling).
Kind regards
Jan