Orange Jelly Fungus on Walnut: Golden Jelly Fungus (Tremella mesenterica)

A mature Oregon walnut has a 4‑ft vertical streak of orange, jelly‑like growth. It’s the fruiting body of Tremella mesenterica (golden jelly fungus), a parasite on wood‑rotting fungi already decaying dead wood under the bark. The slime appears in wet weather, dries in heat. It’s a sign of internal decay but not an immediate killer. If the tree leafs out normally, no action needed. Monitor for other decline signs.