Can you tell if a plant has cryptocarpic fruit? Is it visible from the outside of the cactus? Doesn't sound like it would be easily apparent. Also sounds like an extreme form of seed protection which could easily backfire for the plant. The seeds not only have germination inhibitors, but seem to require age measured in years for a high percentage of germination. Bad combination if the habitat undergoes an unfriendly change. Might make for a precarious existence in a population.
Two of the M. rhodantha fruits were drying up. I pulled them off and looked inside. There were no seeds, so the deflated balloon appearance was an accurate reflection. The remaining two look the same, so it's probably not making any seeds. For a week or two though, the fruits are as colorful as the blooms
