You can find them any time of year but mostly in late Autumn on dead branches and old coppice stumps. They tend to occur on wood that is already well rotted, other fungi having had the first munch. These are less demanding and can get nutrition from wood that is already part decayed. These fruiting bodies are supposed to be slightly bioluminescent but don’t them expect to see them glowing unless it is very dark or you have night vision equipment. Their latin name is Xylaria hypoxylon, they aren’t edible, no surprise there.