Aristolochia sp. flower. Coloured 3D reconstructed computed tomography (CT) scan showing the internal structure of the perianth of a Dutchman's pipe (Aristolochia sp.) flower. The flowering part of this vine acts as a pollination trap. It produces a foul smell that attracts insects. As they crawl inside the long perianth, inward-pointing hairs prevent their escape. The bulbous chamber where the flower meets the stem contains the reproductive parts of the plant which the insects fertilise with pollen. The plant also releases its own pollen onto the insect. The imprisoning hairs wither soon afterwards, allowing the insects to escape covered in pollen, which they carry to other flowers.