Black henbane (Hyoscyamus niger
) is a cultivated, ornamental, highly poisonous, erect biennial or annual plant. In the first year, henbane develops a large leaf rosette, which can at first glance look like cabbage.
During the second growing season, it bolts and flowers from June to August. The plant produces hundreds of seeds from July to October that can remain viable for 5 years or more.
Henbane can group up to 3 feet in height and is covered in glandular hairs, which make the plant feel sticky if touched. It has hairy, coarsely-toothed to shallowly lobed leaves which put off a foul odor. It produces one-sided clusters of funnel-shaped, 5-lobed, greenish to brownish-yellow flowers which have a purple center and purple veins.
The whole plant contains tropane alkaloids (hyoscyamine, atropine and scopolamine). The seeds contain the highest concentration of toxins, although all parts are poisonous. Horses rarely consume henbane due to its foal odor and bitter taste, however if they are without another food source they may.