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. Sylvia= Opal x Cherie registered: 14/11/2002 by Roper N.
Species composition summary:
fitzgeraldii 62.5% hartmannii 31.3% spathulatus 6.3%
Sarco. Sylvia = Opal x Cherie = [Topaz x fitzgeraldii] x [Fitzhart x fitzgeraldii]
Fitzhart = hartmannii x fitzgeraldii
Topaz = Perky x hartmannii = [hartmannii x spathulatus] x hartmannii