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. Aussie Dawn= hartmannii x dilatatus ( has 13 hybrid progeny ) registered: 1/12/1987 by Spence P.
Species composition summary:
dilatatus 50.% hartmannii 50.%
Sarco. Aussie Dawn = hartmannii x dilatatus