Conium maculatum, Poison-Hemlock is a biennial herbaceous plant in the carrot family (Apiaceae) that grows 3-8 ft. (0.9-2.4 m) tall. Stems are stout, hollow, ridged, and purple-spotted. C. maculatum has a thick, white taproot that may easily be mistaken for wild parsnips. All plant parts are poisonous; however, the seeds contain the highest concentration of poison. C. maculatum is native to Africa, temperate and tropical Asia and Europe.
Foliage
Leaves are shiny green, 3-4 times pinnately compound, and clasp the stem at the swollen nodes. Crushed foliage and roots have a disagreeable, parsnip-like odor.
Flowers
Flowers are small, white, and held in umbels about 3 in. (7.6 cm) across (appearing in early summer).
Fruit
C. maculatum reproduces from seed. Fruits are ridged and flattened, and each fruit holds two seeds.
Ecological Threat
C. maculatum contains highly poisonous alkaloids toxic to mammals. Human deaths have occurred from harvesting and consuming the roots as wild carrots or parsnips. C. maculatum quickly colonizes disturbed habitats such as roadsides, old fields, fencerows and ditches. In natural areas it can displace native plant species and prefers riparian habitats. Many U.S states have listed C. maculatum as a noxious weed.