A fern is a type of plant that is not as advanced as trees and flowers. The leaves of a fern are called fronds. Fronds start off tightly curled and uncurl as they grow. Ferns don't grow from seeds, instead they grow from primitive spores. Spores are found in little lumps on the bottom of the fern's fronds, and when they fall out of the lumps they look like fine dust. There are thousands of different kinds of fern.