Without petals; describing a flower or plant that has no petals.
From Greek 'a-' (without) + 'petalon' (petal, leaf-like structure) + Latin '-ous' (having the quality of). The term became standard in botanical nomenclature in the 19th century.
Some of the world's most successful plants are apetalous—think of grasses that feed billions of people, or wind-pollinated trees; they don't need flashy petals because they use wind instead of insects to spread their pollen.
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