I tried crossing them both ways, but it seems that the Gong. scaphephorus flowers are all male! The part of the column where the stigmatic surface should be is just like the rest of the column ... no concave surface, no sticky area, nothing. Seemingly some gongoras only develop a stigmatic surface on a flower if the pollinia of that flower are removed soon after it opens. The Gong. claviodora flowers did have stigmatic surfaces, but the cross didn't take. Maybe these species are incompatible and can't cross pollinate because they belong to two different subsections (Gong. scaphephorus belongs to subsection Scaphephora and Gong. claviodora to subsection Gongora).