Mushrooms growing in houseplants are caused by a fungus. The mushrooms are the fruit of that fungus. One of the most common mushrooms found growing in houseplants is the Leucocoprinus birnbaumii. This is a light yellow mushroom with either a balled or flat cap depending on how mature they are.
Are Leucocoprinus Birnbaumii poisonous?
Leucocoprinus birnbaumii is a species of gilled mushroom in the family Agaricaceae. It is common in the tropics and subtropics, but in temperate regions frequently occurs in greenhouses and flowerpots, hence its common names of flowerpot parasol and plantpot dapperling. The fruit bodies are poisonous, if consumed.