Hyoscyamus

Herbs, annual, biennial, or perennial, taprooted [rhizomatous], glandular-pubescent [glabrous]. Stems simple or branched. Leaves alternate (basal rosettes and cauline), petiolate (cauline leaves may be sessile or petiolate proximally, sessile distally); blade toothed or lobed. Inflorescences terminal [axillary], racemose [cymose], bracts leaflike. Flowers 5-merous, bilaterally symmetric or slightly irregular; calyx not to slightly accrescent, enclosing fruit, tubular-campanulate [urceolate or cup-shaped], 5-lobed, lobes triangular (lobes shorter than to as long as tube), becoming rigid with rigid or spinescent lobe-tips; corolla yellow or white, throat and veins sometimes purple, bilateral, funnelform; lobes spreading, triangular-ovate, shorter than tube, adaxial lobe usually ± larger; stamens slightly unequal, inserted near base or middle of corolla tube; anthers dorsifixed, ellipsoidal, dehiscing by longitudinal slits (introrse); ovary 2-carpellate, (2-locular); style filiform; stigma capitate, ± 2-lobed. Fruits capsules, ellipsoidal, dehiscence circumscissile. Seeds ovate-subreniform, flattened, (surface reticulate to honeycombed, dull or shiny). x = 14, 17.

Distribution

Introduced; Eurasia, n Africa, introduced also in South America, s Africa, Australia.

Discussion

Species 23 (2 in the flora).

Species of Hyoscyamus sometimes are cultivated as ornamentals. They contain toxic alkaloids, including hyoscyamine and scopolamine, which may have medical applications (M. F. Roberts and M. Wink 1998; W. H. Lewis and M. P. F. Elvin-Lewis 2003).

Selected References

None.

Lower Taxa

Hyoscyamus albus, Hyoscyamus niger

Key

1	Mid and distal cauline leaves sessile, blade bases clasping; corolla veins purple.	Hyoscyamus niger
1	Cauline leaves all petiolate, blade bases not clasping; corolla veins pale.	Hyoscyamus albus