Mirabilis jalapa L.—Four o'clock
FAMILY: Nyctaginaceae—The Four o'clock Family
Relatively few members of this family occur in Pennsylvania. A full description of the poisonous plant is given below.
PHENOLOGY: This perennial plant of warmer regions is cultivated in Pennsylvania as a garden annual. It flowers in the summer and is fragrant in the evening hours.
DISTRIBUTION: This widely cultivated plant occasionally escapes to roadsides and wasteplaces.
PLANT CHARACTERISTICS: Four-o'clock is a much-branched, erect plant growing to 1 m tall; leaves: ovate, opposite, deep green, the lower, primary ones petioled, acuminate; flowers: 3.5 cm across, red, pink. yellow, or white, often striped and mottled, opening in late afternoon or during daytime in cloudy weather; calyx tube: corollalike, 2-3 cm, 5-lobed at top, corolla: absent; involucre: 5-lobed, calyxlike, 6-8 mm at flowering; fruit: rounded at the summit, tapered at base.
POISONOUS PARTS: The roots and seeds are reported to be poisonous; herbage should also be considered suspect.
SYMPTOMS: Gastroenteritis, including vomiting, diarrhea, and abdominal pain, are symptomatic.
POISONOUS PRINCIPLES: The toxic principles are unknown.
CONFUSED TAXA: No plant, native or introduced, is readily confused with four o'clock.
SPECIES OF ANIMALS AFFECTED: Children have been poisoned from ingestion of fouro'clock roots and seeds. Livestock might also be susceptible.
TREATMENT: (11a)(b); (26)
OF INTEREST: Mirabilis jalapa has shown some potential as an anticancer chemotherapeutic.