“The Yellow Jade Mushroom grows on Mount Penglai. Its color is yellow, and its taste bitter. Dongwanggong ate it and became immortal, and lived for 90,000 years. The yellow tiger and yellow fish guard it. It consists of three levels; the lower level has three branches.”
—Classification of Supreme Numinous Treasure Mushrooms, from the Taoist Canon of the Zhengtong Reign, MIng dynasty, dated 1445; quoted in Taoism and the Arts of China by Stephen Little with Shawn Eichman, 2000.
You missed the last sentence: its roots are also yellow.
🙂 That’s because I am Chinese.