Further confirmation: among many other very interesting plants photographed at the Montreal Botanical Garden,1 this page includes a Sumurun 'Boholt' that resembles this flower, which is the best I could do for confirmation.
Paphiopedilum Sumurun = Paphiopedilum Boltonii x Paphiopedilum Christopher (Ref.)
I was unable to find photos of either parent, when I looked back in March. I did find a half-sibling (on the Boltonii side) that is also mostly white with some faint spotting, though I apparently didn't save the link so I can't show it to you.
-
1 (In particular, I really like that Lycaste schilleriana 'Our Tropics Daiquiri.')


Looks like that flower had pretty nice/heavy substance.
ReplyDelete