A toadstool was a common type of fungus lifeform which could be found on the planet Earth.
History[]
In 2267, Leonard McCoy and Hikaru Sulu attempted some genetic engineering to develop a variety of cyclone tree on Rimillia resistant to harsh climates. Sulu regarded the results of one simulation as a 30-meter-tall toadstool rather than a tree, too weak to withstand high winds. (TOS novel: Twilight's End)
In 2269, amateur mycologist Sulu inspected a variety of toadstools on the surface of a cloaked planet, keeping one specimen in his pocket to study later. (TOS novel: Assignment: Eternity)
In 2275, McCoy questioned the fungal data in an initial survey report on 1212 Muscae IV, thinking those who wrote the report wouldn't have recognized a toadstool if it jumped on them. He noted one species misidentified as four separate species. Also, a spore-generating species seen in different stages of reproduction was misidentified as three separate species. (TOS novel: Doctor's Orders)
In 2293, James T. Kirk mistook the citizens of the planet Cytrops 469 for edible toadstools. (TOS novel: The Fearful Summons)
In 2369, fungi and toadstools were evident on Ohniaka III. (TNG novelization: Descent)