Which of the following statements best defines the monoecious condition?

Concept

Monoecious (from the Greek mono, meaning 'one', and oikos, meaning 'house') is a plant-level term: a single plant that bears both male and female reproductive organs, most often as separate staminate (male) and pistillate (female) flowers on the same plant — for example maize, cucumber and coconut. It is contrasted with the dioecious condition, in which the male and female organs are borne on separate plants. Note that a single flower which itself contains both the androecium and the gynoecium is, strictly, a bisexual or hermaphrodite flower.

Applying it to the statements

The essence of the monoecious condition is that both sexes — the male androecium and the female gynoecium — are present in the same plant. Among the four statements, only the one describing a flower with both the androecium and the gynoecium includes both the male and the female reproductive parts; the remaining statements describe only a single sex or an unrelated anther feature. Because a structure can carry both sexes only when both whorls are present, this is the statement the exam accepts as the intended, closest-available answer — even though, strictly, monoecy is a property of the whole plant rather than of a single flower.

Comparing the other statements

• A flower with the gynoecium only carries just the female whorl of carpels — a pistillate, single-sex flower — so it represents only one sex.

• A flower with the androecium only carries just the male whorl of stamens — a staminate, single-sex flower — so it too represents only one sex.

• "Dithecous" describes an anther made of two lobes, or thecae; it refers to stamen structure and not to which reproductive whorls a flower bears.

Result

Among the statements offered, the one that includes both the androecium and the gynoecium is the keyed answer, as it is the only choice in which both male and female reproductive parts are present. Note, however, that this wording literally describes a bisexual (hermaphrodite) flower; the term monoecious is, strictly, a property of the whole plant, which bears both sexes — often as separate unisexual (male-only and female-only) flowers on the same plant, such as maize, cucumber and coconut. The option is accepted here as the closest available match rather than as a botanically exact definition, so treat the item as a loosely worded exam question.