''Cicuta douglasii'', the western water hemlock, is a very poisonous

perennial plant In horticulture, the term perennial (''wikt:per-#Prefix, per-'' + ''wikt:-ennial#Suffix, -ennial'', "through the year") is used to differentiate a plant from shorter-lived annual plant, annuals and biennial plant, biennials. It has thus been d ...

in the family

Apiaceae Apiaceae () or Umbelliferae is a family of mostly aromatic flowering plants named after the type genus ''Apium,'' and commonly known as the celery, carrot, or parsley family, or simply as umbellifers. It is the 16th-largest family of flowering p ...

Description

The plant's roots are thick and

tuber Tubers are a type of enlarged structure that plants use as storage organs for nutrients, derived from stems or roots. Tubers help plants perennate (survive winter or dry months), provide energy and nutrients, and are a means of asexual reproduc ...

ous, with many smaller tubers on the main one, allowing survival in wet conditions. The stem is tall with purplish spots. The inner tubers and stem bases can have horizontal chambers useful for identification. The

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

are alternate and compound pinnate; the secondary veins of the leaflets end at the bases instead of the tips of the teeth. The leaflets are long and wide, with jagged edges. Its

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

s are compound umbels about across, with many small, white flowers, which have two seeds each. The seeds germinate in spring, and flowers mature near the end of June and beginning of July.

Seed dispersal In spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, ...

is by means of wind, water, machinery, clothing, and through transported soil. In addition to sprouting new plants from seeds, rootstocks can also produce new plants in the fall from the basal

meristem In cell biology, the meristem is a structure composed of specialized tissue found in plants, consisting of stem cells, known as meristematic cells, which are undifferentiated cells capable of continuous cellular division. These meristematic c ...

. When these detach the following spring, they may form a new plant. Cicuta douglasii leaf detail

Distribution and habitat

Water hemlock is most abundant in

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

, and is indigenous to

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, where it grows primarily from the base of the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of Western Can ...

to the Pacific coast, stretching from

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

all the way to

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. Water requirements limit this plant from inhabiting open rangelands. It grows in wet places such as marshes, stream banks, slough margins, ditches, meadows, and wet pastures.

Toxicity

The main distinguishing characteristic of western water hemlock is its toxicity. Cicutoxin is the

toxin A toxin is a naturally occurring poison produced by metabolic activities of living cells or organisms. They occur especially as proteins, often conjugated. The term was first used by organic chemist Ludwig Brieger (1849–1919), derived ...

that is produced, making water hemlock the most poisonous plant in North America. Cicutoxin is a yellowish liquid that is prevalent in the roots. This unsaturated alcohol has a major impact on the central nervous system of animals. Early symptoms of cicutoxin poisoning include excessive salivation, frothing at the mouth, nervousness, and incoordination. These symptoms can progress to tremors, muscular weakness, seizures and respiratory failure. Ingestion of green materials of western water hemlock in amounts equivalent to about 0.1% of a person's body weight can even lead to death. In addition to being extremely hazardous to humans, this plant has an enormous impact on animals. As little as 0.2–0.5% body weight for sheep, 0.1% body weight for cattle, 0.5% body weight for horses, and 0.3% body weight for swine can be lethal. Death can occur within fifteen minutes of ingesting the toxin. It is one of the first plants to emerge in springtime, and has a very appealing odor. These characteristics, along with the fact that it grows in moist areas, make the plant very attractive, but deadly, to grazing animals.

References

External links

Calflora Database: ''Cicuta douglasii'' (Western water hemlock)

Jepson eFlora (TJM2) treatment of ''Cicuta douglasii''

U.C. CalPhotos gallery
{{Authority control Apioideae Flora of the Northwestern United States Flora of California Flora of Alaska Flora of Nevada Flora of Western Canada Flora of the Sierra Nevada (United States) Natural history of the California chaparral and woodlands Taxa named by Augustin Pyramus de Candolle Taxa named by John Merle Coulter