When you scan the damp understory of Kubah National Park, most fungi catch your eye with vibrant orange shelves or bright white margins. But every now and then, the decaying logs reveal something dark, grotesque, and totally surreal that forces you to stop and lock focus.
Protruding like a piece of melted black plastic or burnt timber from a rotting log was this strange carbon fungus (Xylariaceae, genus Xylaria).
Commonly referred to as “Dead Man’s Fingers” or carbon fungi, these weird Ascomycetes are specialized saprotrophs that consume soft glucans and lignin, leaving behind tough, black, charcoal-like structures.
Anatomy of a Tarry Stroma
While they might look like burnt wood to a casual hiker, a close macro inspection reveals a living, highly specialized fruiting structure:
- Carbonaceous Skin: The outer crust (stroma) is dense, tough, and jet-black, protecting the fungus from drying out in tropical heat while preventing hungry insects from devouring it.
- Microscopic Reproductive Chambers: Embedded just beneath that smooth, dark surface are tiny, flask-shaped chambers called perithecia. When mature, microscopic spores are squeezed out through tiny surface pores (ostioles) to drift off into the rainforest breeze.
- Irregular Morphologies: Xylaria species are notoriously variable in shape—often growing into knobby, twisted, or club-like forms as they push out from cracks in decaying heartwood.
The Unsung Recyclers
Finding strange fungal growths like this Xylaria reminds you that rainforest decomposition isn’t always pretty, but it’s essential. Even on a windy hike back down to HQ where target insects stayed hidden, filling the Minutia Flux logs with diverse fungal forms—from delicate Microporus chalices to carbonized Xylaria clubs—shows the true breadth of Borneo’s understory life.
Field Notes:
- Location: Kubah National Park (Selang to HQ return trail)
- Subject: Carbon Fungus / Dead Man’s Fingers (Xylaria sp.)
- Camera Setup: Canon EOS 60D (Backup run)
- Ecological Role: Soft-rot fungus breaking down tough hardwood components
