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. Iris= Madge x Topaz ( has 2 hybrid progeny ) registered: 10/10/2014 by Roper N.
Species composition summary:
Sarco. Iris = Madge x Topaz = [hartmannii x Snowhart] x [Perky x hartmannii]
Snowhart = Cherie Snow x hartmannii = [Cherie x hartmannii] x hartmannii
Perky = hartmannii x spathulatus
Cherie = Fitzhart x fitzgeraldii = [hartmannii x fitzgeraldii] x fitzgeraldii