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Overview
Conium maculatum is a tall biennial in the carrot family (Apiaceae) reaching 36–96 inches (90–240 cm) tall with a 24–48 inch (60–120 cm) spread. First-year plants form a basal rosette of glossy, dark green, finely 3–4 times pinnately compound leaves up to 20 inches (50 cm) long, resembling fern fronds or large parsley. Second-year stems are erect, hollow, smooth, and distinctively marked with purple to reddish-purple blotches and streaks. Crushed foliage emits a pungent, musty odor described as mouse-like. Flowers are white, small, borne in compound umbels 2–4 inches (5–10 cm) across. Fruit is a pair of rounded, ribbed mericarps 0.1 inch (2.5–3 mm) long. All parts of the plant are highly toxic, containing piperidine alkaloids (coniine, γ-coniceine) that cause respiratory failure in mammals. Ingestion of as little as 0.2% of body weight of fresh foliage is lethal to cattle. The plant caused the death of Socrates in 399 BCE, one of the most documented poisonings in history. A single plant produces 35,000–40,000 seeds that remain viable in soil for 3–6 years. Naturalized widely across North America in ditches, riparian areas, roadsides, and waste ground. Populations are expanding rapidly in the Pacific Northwest.
Native Range
Native to Europe, western Asia, and northern Africa, occurring in moist meadows, streambanks, roadsides, and waste areas from sea level to approximately 5,000 feet (1,500 m). Introduced to North America as a garden plant in the 1800s. Now naturalized across most of the United States and southern Canada, with populations expanding in the Pacific Northwest, California, and the eastern United States.Suggested Uses
Used in toxic plant identification training for veterinary students, livestock producers, land managers, and poison control professionals. Studied in toxicology and pharmacology as a source of piperidine alkaloids. Included in Apiaceae identification courses to teach critical differentiation from edible species such as Daucus carota (wild carrot) and Anthriscus cerefolium (garden chervil).How to Identify
Appearance
Size & Dimensions
Height3' - 8'
Width/Spread2' - 4'
Bloom Information
Flowers from May through July in the second year. Individual umbels bloom for 7–10 days. Compound umbels contain 8–16 umbellets, flowering from the outside inward. In the Pacific Northwest, peak bloom occurs in June. Seeds ripen by July through August, approximately 4–6 weeks after pollination. Pollinated by a wide range of insects including flies, beetles, and small bees.Detailed Descriptions
Foliage Description
Dark green, glossy, finely 3-4 times pinnately compound with a fern-like appearance; leaflets deeply cutGrowing Conditions
Sun Requirements
Requires 4-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight