Cryptogam is a term used to denote a plant that produces spores, as in algae, fungi, mosses, and ferns, but not seeds. The term cryptogam, from the Greek kryptos, meaning "hidden," and gamos, meaning "marriage," was coined by 19th-century botanists because the means of sexual reproduction in these plants was not then apparent. In contrast, in the seed plants the reproductive organs are easily seen; the seed plants have accordingly been termed phanerogams, from the Greek phaneros, meaning "visible.".