Which of the following statements best defines the monoecious?

Correct — C. Of the four statements, only option (c) describes both reproductive whorls being present together: the androecium (stamens, male) and the gynoecium (carpels, female).

The key reads monoecious in its broad sense — male and female parts carried on the same plant, as against dioecious, where the two sexes sit on separate plants.

The other three describe a single whorl, or a feature of the anther, so none of them can carry both sexes at once.

Why the others are wrong

• (a)
  A flower with gynoecium only — A flower with the gynoecium only is pistillate — female. Carrying one whorl is the definition of unisexual, which is the opposite of what the stem is after.
• (b)
  A flower with androecium only — A flower with the androecium only is staminate — male. Unisexual again, so it cannot describe both sexes being present on the same plant.
• (d)
  A flower with dithecous — Dithecous describes an anther built of two lobes. It is a structural detail of the stamen and says nothing about whether female parts are present.

Flowering plants get sorted twice over, and the two sortings are easy to blur.

By the flower: a bisexual flower carries both androecium and gynoecium, a unisexual flower carries one and is staminate or pistillate.

By the plant: a monoecious plant carries both sexes on one individual (maize, cucurbits, coconut), a dioecious plant carries them on separate individuals (papaya, date palm).

The Greek root settles it — oikos is house. One house, or two.

Key facts

• The androecium is the male whorl of stamens and the gynoecium the female whorl of carpels.
• A monoecious plant carries both male and female reproductive structures on one individual, as in maize and cucurbits.
• A dioecious plant carries them on separate individuals, as in papaya.
• A flower carrying both androecium and gynoecium is described as bisexual or hermaphrodite.

Common traps

• Reading monoecious as 'one sex' because mono means one. It means one house, and both sexes share it.
• Being pulled by dithecous, which concerns the anther's lobes and not sex at all.

No directly related past PYQ was found.