I’ve only ever grown the the parachute plant Ceropegia sandersonii once and then not very successfully – just when it was covered in these remarkable flowers I let the soil get too cold and wet and it rotted off, and I haven’t been able to get my hands on another plant since. It comes from South Africa and belongs to a genus of plants that trap insects inside the flower until they effect pollination. Flies carrying pollen crawl in through one of the five openings at the top, crawl down the funnel-shaped tube where downward-pointing hairs prevent them from retreating and are trapped in a chamber at the bottom until they pollinate the flower. Then the hairs wither and the flies escape, carrying more pollen for another cross-pollination. There are numerous Ceropegia species, each pollinated by different insects and some very small. You can see the internal structure of the flower of another species, Ceropegia woodii, also known as the Chain of Hearts, here.