Black henbane [Hyoscyamus
niger L.][HSYNI][CDFA list: C] Photographs
SYNONYMS:common henbane, fetid nightshade, insane root, hogs-bean,
jupiters-bean, henbell, hyoscyamus, symphonica, cassilata
DESCRIPTION:Coarse, erect biennial
or summer annual to 1 m tall. Foliage is covered with sticky glandular
hairs and has a foul odor. Black henbane has been
used medicinally for centuries and is commercially cultivated in Europe for
its alkaloid compounds. All plant parts contain tropane alkaloids (hyoscyamine,
hyoscine or scopolamine, atropine) and are toxic to humans and animals
when ingested. Livestock rarely consume plants because of the unpleasant odor
and bitter taste. Introduced into Eastern North America from Eurasia as a
SEEDLINGS:Cotyledons lanceolate to oblong, 3-5 mm long, 1-2 mm
wide, with a few hairs on the basal margins. Lower midvein terminates
with a gland. Stalk below the cotyledons (hypocotyl) short, visible above
ground only at the earliest stage. Subsequent rosette leaves alternate, +/-
oblong, often with petioles nearly as long as the blades. Margins entire to
slightly wavy. Veins conspicuous, depressed on the upper surface, prominent
below. Petioles and veins covered with long glandular hairs.
PLANT:Stems erect, leafy, branched (biennial
form) or few-branched (annual form), densely covered with long glandular
hairs. Leaves alternate, gray-green, covered with short glandular hairs,
short-stalked (lower) to sessile (upper), oblong to lanceolate, 5-20 cm long,
coarsely toothed to acutely pinnate-lobed, with conspicuous pale veins
covered with long glandular hairs. Lower leaves short-stalked, upper sessile.
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and UNDERGROUND STRUCTURES:Taproot thick,
FLOWERS:June-September. Racemes terminal, leafy, one-sided, +/- coiled
at the tips, with flowers solitary in leaf axils below. Petals fused, funnel-shaped,
unequally 5-lobed, oblique at the opening (limb), 2-3(4) cm long, pale
(greenish-) yellow with conspicuous purple veins and a purple throat.
Sepals fused, urn-shaped, 5-lobed, densely covered with long glandular
hairs at the base, 1-1.5 cm long, enlarging to 2.5-3 cm long
in fruit. Lobes acute, spreading, stiff. Stamens 5 (2 short). Filaments
hairy. Anthers purple. Annual plants often have paler flowers and bloom later
and SEEDS:Capsules ovoid, 0.8-1.5
cm long, 2-chambered, open by a thick lid at the top (circumcissle), loosely
enclosed and concealed by a stiff, prominently veined calyx (sepals
collectively). Seeds numerous, brown to gray, deeply pitted, flattened, ~
1.5 mm long, variably shaped, oval to +/- square, contain a higher concentration
of alkaloids than leaves or roots.
HABITAT:Disturbed open sites, roadsides, fields, waste places, abandoned
gardens. Grows best in sandy or well-drained loam soils with moderate fertility.
Does not tolerate waterlogged soils.
DISTRIBUTION: At publication time, no infestations are known to exist in
California. Plants previously eradicated occurred in Modoc, Siskiyou, and
Mendocino cos. Scattered throughout most of the U.S. and Canada.
by seed. Seeds that mature early in a season typically produce biennial
plants. Seeds maturing late in a season often produce annual plants. Newly
matured seeds germinate without light. Seeds that become dormant germinate
best when exposed to light. Under field conditions, seed can remain viable
for ~ 4 years. Biennial seedlings require a cold moist period to induce stem
elongation and flowering. In colder, more northern regions the proportion
of annual plants is higher than in more southern clines.
FAVORING/DISCOURAGING SURVIVAL:Prevent seed
production by cultivation, hand pulling, or mowing plants. Plants with mature
fruits can be burned to kill seed.
SPECIES: Black henbane is unlikely
to be confused with other species in the nightshade family because of its
distinctive flowers and fruits.
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Prevention and control:
Black henbane and prickly comfrey are native to Europe, and were likely introduced
to the United States as medicinal herbs. Both species may be very toxic to
humans and animals, although grazing animals will not consume black henbane,
unless other forage is unavailable. Black henbane is in the Solanaceae family
and prickly comfrey is in the Boraginaceae family.
Black henbane was found in Modoc, Siskiyou, and Mendocino Counties, but has
been eradicated. No new populations have been detected in California. However,
it is occasionally found throughout the United States and has repeatedly demonstrated
its ability to escape cultivation. It may live as an annual or biennial and
reproduces solely by seed. The entire plant has an extremely foul odor. Any
plants found should be reported to the County Agricultural Commissioner and
immediately destroyed. Plants should be hand pulled (gloves are strongly recommended)
or dug, making sure that the thick, fleshy, taproot is completely removed.
Plants detected with mature fruits should be carefully placed in bags to prevent
seed dispersal, and the area should be monitored for new seedling emergence
for at least four years. If the infestation is too large for hand pulling,
a systemic herbicide, such as glyphosate should be applied. Glyphosate is
nonselective, but should provide effective control. The area should be monitored
after application and any escapes or regrowth should be retreated.
Prickly comfrey is well established in areas of the North Coast Range, and
in the Sacramento Valley in Yolo County. The source of introduction into California
is uncertain. It has been grown as a forage crop in Russia and as a herbal
remedy around the world. It thrives on moist, fertile, soils and is cold tolerant
to some extent. The perennial nature of this plant increases the difficulty
in control. It tends to form large distinct clumps with a deep taproot and
can produce new plants from small pieces of severed roots. There is no information
regarding herbicide efficacy on prickly comfrey. However, glyphosate is effective
for controlling rough comfrey. Retreatment may be necessary on large clumps
if regrowth occurs. Repeated cultivation may be effective, but may also spread
severed roots to new areas.