It's sauerkraut

According to many old people, many people ate this wild dish in the '60s and '70s, and in times of famine, they ate whatever they could, what they couldn't eat, what they used to eat, simply because they were poor. It is called common algae, known as molybdenum, ground cabbage, soft ground and groundbread, a combination of fungi and algae, usually grown in dark and humid areas, dark black, and somewhat like soft black molybdenum ears. Studies have shown that common algae contain many nutrients and that their protein content is higher than eggs, wooden ears, silver ears, etc.; total amino acid content is similar to that of hairy vegetables, mushrooms, so common algae is a good source of human protein. In the countryside, there is a mustache, which comes after the rain, and the little partners who have eaten are happy. It is extremely rare for this type of wood to be flat, but it is often found in uncontaminated hills or grasslands after heavy rains。