Donald, I went to the database and typed Croton into the search box and then clicked on "View all plants in the Genus Croton". I see that Codiaeum variegatum shows up on page 20:
http://garden.org/plants/brows... It is confusing to see a Codiaeum listed in the Croton Genus but I'm thinking it shows up in the list because it has synonyms of Croton johannis and Croton angustissimus. That way if someone were looking for C. johannis or C. angustissimus it would take them to the correct plant.
I sometimes get confused with the database though so maybe one of the DB Moderators can clarify.
@Calif_Sue @KentPfeiffer @zuzu