Incomplete and imperfect flowers

Some flowers are missing parts.

A complete flower has pistil(s), stamens, petals and sepals. An incomplete flower is missing at least one of these parts.

A perfect flower has both sexes (both stamens and pistils). An imperfect flower is missing either the stamens or the pistils: it is unisexual. Imperfect flowers that are missing pistils are called staminate flowers. (They have stamens.)   Imperfect flowers that are missing stamens are called pistillate flowers. (They have pistils.)

In some species individual plants may have only staminate flowers or only pistillate flowers. These species are considered "dioecious", a term meaning "two houses". Species in which individual plants bear both pistils and stamens somewhere on them are termed "monoecious" (one house). Note that monoecious species may have either perfect flowers or imperfect flowers.   If they have imperfect flowers, however, both staminate and pistillate flowers have to occur on the same plant for the species to be monoecious.

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