I am currently working on a setting which is fantasy but based around a soft approach to speculative biology.
It is a tidally locked world with the habitable region based around the terminator between the bright hot sun side and the freezing dark, filled with terran descended flora/fauna. The main continent is bisected by a long range of extremely tall volcanic mountains. The south, where sunlight is more plentiful, is relatively similar to terran plant life. But the north, where it goes from twilight to darkness, is where things become much more alien.
One of the ecosystems I want to use are forests of fungal plants in place of trees, located near the ocean in a vague analogue to Europe. My biology isn't the best but I know fungi feed off dead matter.
My question isn't if it could work, but rather how it could work. I was thinking an underground system of dead matter running off into the ocean that the fungi reach down to consume. Also possible there are lots of megafauna which migrate across the continent to pass away in these area, feeding the forest as they decompose.
This setting is fantasy so 100% plausibility isn't necessary (think Dougal Dixon or Flight of Dragons).