Rosellinia Subiculata

Often overlooked by casual hikers, Rosellinia subiculata looks like a cluster of tiny black pearls resting on a golden velvet rug. Known colloquially as a type of "Carbon Ball" or "Dotted Cup," this fungus plays a quiet but vital role in recycling the forest's fallen timber. While it doesn't have the classic umbrella shape of a toadstool, its striking contrast of black spheres against a yellow base makes it a hidden gem for macro-photographers.

🔍 How to Identify

• 🌑 The Perithecia: The main body consists of tiny, black, spherical structures (perithecia) that are usually less than 1mm in diameter, often appearing like scattered buckshot or black peppercorns.
• 🟡 The Subiculum: This is the most identifying feature; the black spheres sit on a thin, felt-like mat of mycelium that is bright sulfur-yellow or mustard-colored when fresh, eventually fading to a dull tan or brown.
• 🕳️ The Ostiole: Under a magnifying glass, you can see a tiny, nipple-like pore at the top of each sphere through which the fungus shoots its microscopic spores into the air.

🌲 Habitat & Ecology

• 🪵 Woodland Recycler: This fungus is saprobic, meaning it feeds exclusively on dead organic matter. You will typically find it colonizing well-decayed logs of hardwood trees like Oak, Beech, or Maple, especially those that have already lost their bark.
• 🌧️ Moisture Seeker: It thrives in the damp, shaded microclimates of the forest floor. It is most visible during late summer and autumn when consistent rainfall triggers the growth of its colorful yellow "carpet."

⚠️ Safety & Toxicity

• 🚫 WARNING: Rosellinia subiculata is strictly non-edible. Because of its tiny size and hard, charcoal-like texture, it has no culinary use whatsoever.
• 🐾 Pet Safety: While not known to be aggressively toxic to the touch, it should not be ingested by humans or pets. Its tough structure can cause digestive distress, and many wood-rotting fungi contain compounds that are poorly understood by science regarding their chemical safety.

✨ Fun Fact

The species name subiculata refers to the "subiculum"—the felt-like mat it grows on. This "golden rug" is so distinct that it acts like a biological ID card, helping mycologists distinguish it from dozens of other tiny black "carbon" fungi that grow directly on bare wood without a colorful foundation.