They lack the enclosed chambers in which angiosperm seeds develop. The earliest vascular plants were seedless and the ferns belong to one of the four living divisions of plants that have retained this early condition. Of all seedless vascular plants, ferns are the most extensively represented in the modern flora. Ferns disperse via spores, rather than seeds. Unlike seeds, each spore has half the complement of genetic material.
Sexual reproduction occurs later in the life cycle.
The leaves, or fronds, of ferns are compound, meaning each leaf is composed of several leaflets called pinnae. The frond grows as its coiled tip, the fiddlehead, unfurls. The leaves usually sprout directly from a horizontal underground stem called a rhizome such as they do in brackens and sword ferns. Large tropical tree ferns, by contrast, have upright stems many meters tall. The leafy fern plant familiar to us is part of the life cycle called the sporophyte generation.