Some polypody Polypodium vulgare ferns continue producing spores deep into winter and if you turn over a few fronds you’re eventually likely to find these golden cluster of sporangia. Unlike many ferns, the sporangia of this species are not covered by a membrane during their development and under the microscope they resemble nests of golden eggs, or maybe even party balloons if you're in a celebratory frame of mind.
Each sporangium is packed full of spores and when they’re ripe there’s a remarkable mechanism for catapulting spores out into the airstream, that you can read about at http://beyondthehumaneye.blogspot.com/2009/07/natures-siege-catapults.html
The gaping sporangium at the top of this picture (above) has burst open and has already catapulted out most of its spores. You can still see the spores packed into the surrounding unripe sporangia, through their transparent walls
Polypody spreads vegetatively with creeping rhizomes, that either grow over the branches of trees or through old walls, and you can see it in its habitat over at http://cabinetofcuriosities-greenfingers.blogspot.com/2009/11/wall-ferns.html
