Fungi Aren't Plants: Inside a Mushroom Cell
In a forest in eastern Oregon, one single living organism spreads across about 2,400 acres — roughly 1,900 football fields. It's not a giant tree or a herd of animals. It's a fungus called Armillaria ostoyae, and most of it lives hidden underground as thin threads you'd need a microscope to fully appreciate.
What You'll Learn
By the end of this lesson, you will be able to: - Explain why fungi are classified separately from plants and animals - Describe what makes up a fungal cell wall - Define hyphae and mycelium and explain how they connect - Describe how a giant fungus like Armillaria ostoyae can grow so large
Not a Plant, Not an Animal
For a long time, scientists grouped fungi with plants because both often grow from the ground and stay in one place. But fungi are different enough that scientists now place them in their own kingdom entirely: Kingdom Fungi. Unlike plants, fungi have no chlorophyll and cannot make their own food from sunlight. Instead, fungi absorb nutrients from whatever they're growing on or in — dead leaves, wood, soil, or even other living things.
Inside a Fungal Cell
A plant cell's wall is built mainly from a tough material called cellulose. A fungal cell's wall is built from a different tough material called chitin — the same substance found in the shells of insects and crabs. This is one of the clearest clues that fungi are more closely related, biologically, to animals than to plants, even though they don't look or act like either one.
The mushroom you see poking out of the ground is only the fungus's fruiting body — the part built to release spores, like a plant's flower. The vast majority of the actual organism lives out of sight underground or inside wood, as a hidden network of threads.
One Mushroom, Miles of Threads
Those hidden threads are called hyphae — thin, branching filaments, each too small to see without a microscope. A single fungus's hyphae spread out and tangle together into a huge underground network called mycelium. In a giant fungus like Armillaria ostoyae, mycelium can spread for miles underground and live for thousands of years, making it, by area, one of the largest and oldest living organisms ever found on Earth.
Flashcards — click each card to reveal the answer
What is chitin, and why does it matter for classifying fungi?
What part of a fungus does a visible mushroom represent?
Map a Mycelium Network
On paper, draw a mushroom above the ground and then draw a branching network of thin lines (hyphae) spreading underground beneath it, connecting to at least 3 other mushrooms. Label the mushroom cap as the 'fruiting body' and the underground network as 'mycelium.' Write one sentence explaining which part does most of the fungus's actual living and feeding.
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