Building mushrooms on the surface in Mycelarium is how the colony works above ground: the mushroom stands on the grass line with its hyphae running down into the soil, and from that position it drifts spore particles and catches falling leaves. It is the one placement that ties the underground network to the forest above it.
Mycelarium building mushrooms on the surface: what they do
- They drift spores. Spore particles come off a surface mushroom and blow away from the colony.
- They catch falling leaves. Leaves that drop onto a surface mushroom decay into food, which is the renewable food source.
- They can be carried off. Surface mushrooms are exactly the ones a hedgehog takes.
The forest above is alive but not hostile: leaves fall and decay into food, hedgehogs wander across the surface, and trees can become future sources of nutrients. The demo gives little guidance on why placing mushrooms above ground is worth it — players ask for more nudging on that — but the answer is the two jobs below.
Where the spores drift
Drifting spore particles blow away from the colony, and a spore that lands seeds a new growth point you can grow from. That is how a gap too wide for a hypha gets crossed. The upgrades that decide how many spores fly and how well they carry are Spore Count and Spore Quality, with Spore Lightness beyond that. The whole mechanic is in wind carried spores.
Where the leaves have to land
The leaf side of surface building only works if the network is close enough to the grass line for the leaves to reach it, which is why leaf mulching is used by running the mycelium up under the leaf fall. That is in leaf mulching.
The catch with surface mushrooms
Surface mushrooms are the ones a hedgehog takes, and it takes them about ten seconds after you place one, with no warning. The Repeller Mushroom is what handles it. What to do about it is in how to stop hedgehogs eating mushrooms.