A fern is a type of plant that grows feathery, delicate-looking leaves but never produces flowers. Instead, ferns reproduce through tiny dust-like particles called spores that form on the undersides of their leaves. If you flip over a fern's leaf, you might see neat rows of brown dots or patterns, which are clusters of these spores.

Ferns thrive in shady, damp places like forest floors, where their graceful fronds (the word for fern leaves) can unfurl and spread. Some ferns grow just a few inches tall, while tree ferns in tropical rainforests can tower over your head. Many people grow ferns as houseplants because their lush green leaves add life to indoor spaces.

Ferns are ancient plants that covered Earth millions of years ago, long before most flowering plants existed. Dinosaurs walked among giant ferns, and over time, layers of dead ferns and other plants were compressed underground to form some of the coal people use today. When you see ferns growing wild in a forest or potted on someone's porch, you're looking at descendants of some of the oldest plants on the planet.