No Sex Yet????

I just harvested one of my plants but there's still one out there that hasn't shown any signs of sex - male, female, OR hermi. There aren't pollen sacks or pistiles. Now, this plant had it's top cola snapped (but fixed...) but I didn't think that'd be enough to shock it into doing nothing... Now all things considered my grow was just a bunch of random bag seed so that might have had something to do with it but what's going on??? Just a REALLY late flowering Sativa???