Priscilla Long profiles the white button mushroom:
This common, commercially grown (and naturally growing) fungus, Agaricus bisporus, belongs to the kingdom of fungi, equal in status to the animal kingdom and the plant kingdom. Before genomics revealed true evolutionary relationships, fungi were considered first cousin to plants. The new Tree of Life puts them closer to animals. And, like us, they can’t synthesize sugars out of sunlight and must eat organic plant matter, such as dead wood and dried autumn leaves. Unlike us though, fungi grow toward their food. When they reach lunch, they excrete an enzyme that breaks it down outside their body. Only then do they ingest it. Digestion before ingestion.