water hemlock(redirected from water hemlocks)
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Related to water hemlocks: spotted water hemlock
water hemlock:see poison hemlockpoison hemlock,
lethally poisonous herbaceous plant (Conium maculatum) of the family Umbelliferae (parsley family). It has rank, finely divided foliage, flat-topped clusters of small white flowers, and a hollow, purple-mottled stem.
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(Cicuta), a genus of plants of the family Umbelliferae. Perennial water or marsh grasses with double or quadruple pinnate leaves. Small white blossoms, gathered into compound umbels. Fruit mostly rounded with mericarps slightly compressed on the sides. About ten (by other data, up to 20) species, mainly in North America.
In the USSR, the Eurasian species, C. virosa, is widespread: stalk hollow, height 50-150 cm; leaves double or triple pinnate; vertical rhizome divided into chambers by septa. The plant grows in marshes, on wet meadows, in alder thickets, and along swamped banks of rivers, lakes, and ditches. This is one of the most poisonous plants of the flora of the USSR. Especially dangerous are the rhizome and roots, which contain the poisonous substance cicutoxin. Domestic animals (chiefly cattle and sheep) are poisoned most frequently in autumn or spring. In intoxication, there is salivation, restlessness, distention of the rumen, frequent discharge of feces and urine, and convulsive contraction of the jaws. Characteristic are repeated tonic spasms (with prolonged contraction of muscles) and collapse of the animal, rapid pulse, and slow respiration. Death results from suffocation. Treatment consists of the immediate use of tannin, carbon, and laxative and cardiac (caffein) drugs; in the event of convulsions, chloral hydrate is used.