I encountered this species of mushroom for the first time in my life, and what's more, it was very close to home, because in the park I go to every day.

The fungus in question is the northern sponge fungus (Climacocystis borealis), a very rare species in Europe. It is generally found primarily on conifers such as spruce, fir, pine, and larch.

Although rare, it also appears on deciduous trees such as ash, beech, poplar, maple, and oak. I had the opportunity to observe this specimen on a deciduous tree.

The mushroom often has an undefined shape and appears to be spreading across the tree. Generally, its cap does not exceed 15 cm in width and 3 cm in thickness, although these figures are highly relative. It is an annual mushroom that appears in summer and dies off in autumn.

The mushroom cap is initially yellowish, creamy, and becomes slightly creamy with age, with hints of white. It grows sideways to the trunk, often emerging from tree cavities, and the fruiting bodies may be fused together, creating an irregular shape.

From the bottom of the mushroom, characteristic tubes up to 5-6 mm long are visible, which with age change into something resembling a labyrinth.

The young fruiting body secretes a liquid from the cap and appears to be weeping. This is not a result of precipitation, and this occurs even on hot days. The white flesh is very soft, elastic, and spongy, with a white color and a very pleasant mushroom-like odor.

The mushroom can be found in North America, Asia, and Europe. It's a rare, endangered species. Although it's a parasite that causes white rot in wood, it's protected in Poland, the Netherlands, Denmark, and Germany. In most countries, it's considered inedible, but there are exceptions, as it's reportedly consumed in Mexico.

And this is what a young fruiting body looks like, photographed a few days earlier, when it was still crying.