Physostigma venenosum (the Calabar bean or ordeal bean) is the seed of a leguminous plant, a native of tropical Africa, poisonous to humans. It derives the first part of its scientific name from a curious beak-like appendage at the end of the stigma, in the centre of the flower; this appendage, though solid, was supposed to be hollow (hence the name from φῦσα, a bladder, and stigma).