Wild mushrooms with a thick stem and a fleshy cap, nutty and slightly meaty. Yunnan sells many kinds fresh in mushroom season and dried; some cause hallucinations unless fully cooked.
Name reflects the mushroom's appearance: the spongy, pore-filled underside of the cap looks like the cross-section of a cow's liver - 牛肝 'cow liver' + 菌 'fungus'.