While some seeds retain their vitality or power of germinating for twenty years or more, it is generally safer to utilize fresh and well-ripened seed to secure good plants. The stories circulated as to the seeds of "mummy" wheat germinating after two thousand or three thousand years have been discredited long ago, and need not be considered. As a rule, fleshy seeds like Peas, Beans, Acorns, Horse-chestnuts, Sweet Chestnuts, and Walnuts lose their germinating powers more readily than smaller and less fleshy seeds; but the latter also deteriorate if kept more than two or three years. In the case of Cucumbers and Melons, growers generally consider that they obtain a greater percentage of plants from two-year-old seed than from one-year-old, which would rather indicate that they require a further period to mature properly after being taken from the fruit and cleansed.