A flower is complete if it has all four main parts of a flower:
Complete flowers include those of hibiscus, roses, buttercups, and nasturtiums.
An incomplete flower is one that lacks any of the four main parts: corolla, calyx, stamen, or pistil.
Flowers that lack petals are called apetalous flowers.
Incomplete flowers include the flowers of trees, such as oaks and hazels, and those of grass plants such as corn, wheat, and oat.
A perfect flower is one that has both the male and female reproductive parts — that is, both the stamen and the pistil.
Lilies, apple flowers, St. John’s wort, hibiscus, and roses are all examples of perfect flowers.
If a flower only has the male (stamen) or the female (pistil) reproductive parts, it is called an imperfect flower.
Flowers that have only female parts are called pistillate flowers.
Flowers that have only male parts are called staminate flowers.
Sometimes a plant can have both male flowers and female flowers on one plant. These plants are called monoecious plants. Monoecious comes from the Greek words monos (meaning single) and oikos (meaning house) — thus, male and female flowers are in a single “house” (a single plant).
Plants that have male and female flowers on separate plants are called dioecious (di + oikos) plants. They are considered both incomplete and imperfect flowers.
An example of a plant with imperfect flowers is the corn plant. It contains two flowers:
Holly and begonia are other examples of imperfect flowers.
Corn, cucumber, squash, other gourds, beeches, and oaks are monoecious — they have both male and female flowers in a single plant.
Soybeans, asparagus, kiwi, and hemp are examples of plants that are dioecious — male and female flowers are “housed” in separate plants.
Other examples include cottonwoods, willows, and many members of the family of cashews and poison oak.
Yes. Some flowers may have both male and female reproductive parts but lack a corolla (petals) and/or a calyx (sepals).
An example is the American elm. It doesn’t need sepals because the flowers are protected by winter buds, and because it is wind-pollinated, it doesn’t need petals to attract pollinators.
Yes. By definition, if any part of a flower is missing, a flower is considered incomplete. Since imperfect flowers don’t have either the male or the female reproductive parts, they are also necessarily incomplete.
A flower is solitary if there is only one flower growing from the stem.
Solitary flowers include the rose, tulip, and narcissus.
If there is a cluster of flowers on one stem, it is considered inflorescent. The cluster of flowers is called an inflorescence.
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