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. Arcadia
= Lois x Fitzhart ( has 5 hybrid progeny ) registered: 1/12/1986 by Banks, DavidSpecies composition summary:
hartmannii 50.% ceciliae 25.% fitzgeraldii 25.%
Detailed composition:
Sarco. Arcadia = Lois x Fitzhart = [ceciliae x hartmannii] x [hartmannii x fitzgeraldii]