To confirm the registration of an Australian native hybrid & view its composition/progeny: (Database as at 1st January 2020 RHS registrations)
For non-Australian Dendrobium hybrids use the Dendrobium Hybrids checklist here
Sarco. Geordi= George Colthup x Heidi registered: 13/11/2006 by Roper N.
Species composition summary:
hartmannii 75.% falcatus 12.5% fitzgeraldii 12.5%
Sarco. Geordi = George Colthup x Heidi = [Melba x hartmannii] x [Fitzhart x hartmannii]
Fitzhart = hartmannii x fitzgeraldii
Melba = hartmannii x falcatus