To confirm the registration of an Australian native hybrid & view its composition/progeny: (Database as at 1st April 2018 RHS registrations)
For non-Australian Dendrobium hybrids use the Dendrobium Hybrids checklist here
Sarco. Velvet= Nicky x Riverdene ( has 30 hybrid progeny ) registered: 9/03/1998 by Finch N.
Species composition summary:
Sarco. Velvet = Nicky x Riverdene = [fitzgeraldii x hirticalcar] x [hartmannii x hirticalcar]