What is "physostigma venenosum"

Physostigmine \Phy`so*stig"mine\, n. (Chem.) An alkaloid found in the Calabar bean (the seed of Physostigma venenosum), and extracted as a white, tasteless, substance, amorphous or crystalline; -- formerly called eserine, with which it was regarded as identical.

Calabar \Cal"a*bar\, n. A district on the west coast of Africa.

Calabar bean, The of a climbing legumious plant ( Physostigma venenosum), a native of tropical Africa. It is highly poisonous. It is used to produce contraction of the pupil of the eye; also in tetanus, neuralgia, and rheumatic diseases; -- called also ordeal bean, being used by the negroes in trials for witchcraft.

Eserine \Es"er*ine\ (?; 104), n. [From native name of the Calabar bean: cf. F. ['e]s['e]rine.] (Chem.) An alkaloid found in the Calabar bean, and the seed of Physostigma venenosum; physostigmine. It is used in ophthalmic surgery for its effect in contracting the pupil.

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 , a bladder, and stigma).