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The 111 pages that link to Flowering plant, each with the reason it gives.
GymnospermCompared with: Enclosed seeds distinguish angiosperms from gymnosperms.
CycadCompared with: Unlike cycads, angiosperms enclose their seeds and reproduce using flowers.
EquisetumCompared with: Horsetails have neither flowers nor fruits, relying instead on spores.
PinalesCompared with: Unlike Pinales, angiosperms enclose their ovules within carpels.