The orchid Phragmipedium Mary Bess is a hybrid registered with the Royal Horticultural Society by R.Brunner in 1991. It is originated by L.Hegedus
Top three species ancestors and their influences are

• Phragmipedium besseae (50.00%)  section: Micropetalum 
• Phragmipedium caricinum (50.00%)  section: Himantopetalum