A flowering plant of Arum apulum, showing the spadix ( vertical column, centre) enclosed within a leaf-like spathe. Arum species have a complex cross-pollination mechanism. The flowers are at the base of the spadix inside a spherical chamber made by the spathe. This is a trap for small flies, lured by the smell of the spadix. The flies fall into the chamber past a ring of bristle-like sterile flowers, which prevent escape. Female flowers within the chamber are receptive at this time, and are pollinated by any flies that bear pollen. After one night, the female flowers dry out, and the (male) anthers open, producing pollen, which coats the trapped flies.The bristles then dry out, and the flies escape to visit another Arum plant. A. apulum is an endangered species on the IUCN red list. Endemic to Apulia in Italy, it is available in commerce, and is a striking perennial garden plant.