The Collaborative International Dictionary
Hyoscyamine \Hy`os*cy"a*mine\, n. [See Hyoscyamus.] (Chem.) An alkaloid found in henbane ( Hyoscyamus niger), and regarded as its active principle. It is also found with other alkaloids in the thorn apple and deadly nightshade. It is extracted as a white crystalline substance, with a sharp, offensive taste. Hyoscyamine is isomeric with atropine, is very poisonous, and is used as a medicine for neuralgia, like belladonna. Called also hyoscyamia, duboisine, etc.
Hyoscyamus \Hy`os*cy"a*mus\, n. [L., fr. Gr. ?; ? a sow, hog + ? a bean.]
(Bot.) A genus of poisonous plants of the Nightshade family; henbane.
(Med.) The leaves of the black henbane ( Hyoscyamus niger), used in neuralgic and pectorial troubles.
Henbane \Hen"bane`\, n. [Hen + bane.] (Bot.) A plant of the genus Hyoscyamus ( Hyoscyamus niger). All parts of the plant are poisonous, and the leaves are used for the same purposes as belladonna. It is poisonous to domestic fowls; whence the name. Called also, stinking nightshade, from the fetid odor of the plant. See Hyoscyamus.
Wikipedia
Hyoscyamus niger, commonly known as henbane, black henbane or stinking nightshade, is a poisonous plant in the family Solanaceae that originated in Eurasia, though it is now globally distributed.