The more common opposite of cleistogamy, or "closed marriage", is called chasmogamy, or "open marriage". Virtually all plants that produce cleistogamous flowers also produce chasmogamous ones. The principal advantage of cleistogamy is that it requires fewer plant resources to produce seeds than does chasmogamy, because development of petals, nectar and large amounts of pollen is not required.
The typical opposite of cleistogamy, or "closed marriage", is chasmogamy, or "open marriage". Nearly all plants that produce cleistogamous flowers also generate chasmogamous ones. The primary advantage of cleistogamy is that it requires fewer plant resources to create seeds than does chasmogamy, as the development of petals, nectar, and large amounts of pollen is not necessary.