They are called non-seed bearing plants. Non-seed bearing plants reproduce without seeds. They produce spores instead. Spores are tiny reproductive cells that grow into new plants. One plant may make millions of spores.
Ferns are one type of seedless plant.
The spores of ferns grow on the underside of the leaves. Ferns have transport tubes to carry food and water. Moss is another type of seedless plant. The spores of a moss form in a capsule on top of a small stalk. Mosses do not have transport systems or veins, instead food and water move from cell to cell.