I would like to disagree but i forget the science of why some plants make an imperfect male organ (probably female too) as oppose to the fully formed one, the example here being the nanna and the whole sac.
You have made reference, i believe, to the nanna not genetically being of a different genetic group 'Hermie burnetalium' but the pollen sac being this latter Hermie b. genetic group.
I think in this case the claim deserves at least an answer to the first of my observations in that you could provide a better answer to why we see a nana not the full pollen sac in the first instance.