Dried fungus has a pungent acetic acid smell and can't be eaten. If it smells musty, pungent or other peculiar smell, it is likely to be improperly processed or stored or processed with chemicals. Auricularia auricula, also known as black vegetables, auricularia auricula and auricularia auricula, belongs to the genus Auricularia and is a precious edible and medicinal gum fungus in China.

Auricularia auricula grows on broad-leaved trees such as oak, elm, poplar, banyan and locust, or on rotten wood and coniferous fir, which can cause wood decay. Auricularia auricula is leaflike or forest-like, with wavy edges, thin, 2 ~ 6 cm wide and about 2 mm thick, with a short lateral stalk or a narrow base, which is fixed on the substrate. At first, it was soft colloid, sticky and elastic, and then it was slight cartilage. After drying, it shrinks strongly and turns into black hard and brittle keratin, almost like leather. The outer edge of the back is curved, purple-brown to dark blue-gray, with sparse short fluff.