Seeds are not produced by Mosses and ferns. Instead they reproduce by means or spores. Sex cells is developed in a moss plant amongst the leaves of its small shoots. Through the thin film of water on the leaves the male cells reach female cells, by swimming. However, the fertilized female cell does not develop either into a seed or directly into a new moss plant. Stalked capsule is developed, which contains thousands of tiny spores. The spores are released, when the capsule is ripped. Each one can produce at least one new moss plant. On the leaves of the adult plant the spore of ferns develops. A spore develops into a tiny heart-shaped structure called a prothallus, when it lands on the ground. This produces male and female cells. Only the tiny prothallus has to be wet. In much drier conditions the adult fern can live.