According to local people, mushrooms grow a lot during the time the acacia trees begin to lose their leaves. This is especially true after rainy days when the fungus begins to sprout on the fallen leaves.
Visitors to some districts of Tay Son, Phu My, and Phu Cat District can see groups of people visiting the large acacia forest to look for mushrooms in the early morning.
A local woman, Nguyen Thi Luu, said that she went with neighbours to look for mushrooms every day.
"This kind of mushroom only appears for some two months during autumn," she said. "It gives the best taste during the first 2-3 days of growing, so we have to try to pick it early."
Luu said that the mushrooms have a light violet colour and taste a bit bitter at first, then give a sweet taste.
"The mushrooms can be made into many dishes which are a local speciality," she said. "They can be used for the fillings of pancakes, stew with chicken, pork, or stir fry with beef.
Luu and her neighbour can pick between 20-30 kilos of mushrooms a day which can be sold for VND30,000-40,000 per kilo.