common water hemlock

(Cicuta maculata var. maculata)

Conservation Status
common water hemlock
Photo by Luciearl
  IUCN Red List

not listed

     
  NatureServe

N5 - Secure

SNR - Unranked

     
  Minnesota

not listed

     
           
Wetland Indicator Status
     
  Great Plains

OBL - Obligate wetland

     
  Midwest

OBL - Obligate wetland

     
  Northcentral & Northeast

OBL - Obligate wetland

     
           
 
Description
 
 

Common water hemlock is a 2 to 7 tall, erect, perennial forb that rises on one or more stems from several fleshy, tuberous roots. The foliage has a foul smell.

The stems are erect, unbranched or branched at the top, stout, hairless, hollow, and often covered with a whitish, waxy bloom (glaucous). They may be green or purple. Mature stems are green with purple spots or stripes. The base of the stem is enlarged.

The main stem leaves are alternate and are divided into 3 segments (ternate). Each segment may be again divided into 3 sections (biternate). Each ultimate section is divided into usually 3, sometimes 5 leaflets (pinnate). The lower leaves are up to 18 long and 8 wide, becoming progressively much smaller as they ascend the stem. The uppermost leaves are sometimes undivided. The leaves are on 4 to 12 long leaf stalks, longest near the bottom of the stem, shorter near the top. The leaf stalks form a sheath at the base that wraps around the stem. The leaf nodes are purplish.

The leaflets are narrowly lance-shaped, 1 to 5 long, ¼ to 1½ wide, and hairless. They are often folded upward along the main vein. The margins have sharp, forward-pointing teeth. The leaflet nodes are purplish. The radial veins of the leaflet extend to the notches between the teeth, not to the tips of the teeth as in other members of the carrot family. The main leaflets of the middle and upper leaves are less than 5 times as long as wide.

The inflorescence is a compound umbel at the end of the stem and each branch. The umbels are round and 1½ to 5 in diameter. They are composed of 10 to 20 umbellets. They are not subtended by bracts.

The umbellets are on stalks (rays) 2 to 2 long. Each one has 14 to 27 individual flowers on stalks (raylets) up to 1 long.

The flowers are about wide with 5 white, rounded, erect to spreading petals and 5 white stamens. The petals are notched at the tip.

The fruit is dry, dark brown to reddish-brown, 1 16 to long, broadly oblong-eliptic, and flattened laterally. It contains 2 seeds and when ripe splits into 2 one-seeded segments. Each segment (mericarp) has 5 ribs: an upper (dorsal) rib; two lateral ribs; and between each lateral rib and the dorsal rib, an intermediate rib. The ribs are blunt and somewhat corky. The dorsal and intermediate ribs are smaller than the lateral ribs and are as wide or wider than the space between the ribs. The lateral ribs are smaller than the oil tube.

The seeds are flattened on one side, rounded on the other.

 
     
 

Height

 
 

2 to 7

 
     
 

Flower Color

 
 

White

 
     
 

Similar Species

 
 

In water hemlocks the radial veins of each leaflet extend to the notches in the leaflet margin, not to the tips of the teeth as in other members of the carrot family.

Bolander’s water hemlock (Cicuta maculata var. bolanderi) mericarp dorsal and intermediate ribs are much narrower than the space between the ribs. The lateral ribs are larger than the oil tube.

Bulbet-bearing water hemlock (Cicuta bulbifera) has bulbils at the leaf axils of some of the upper leaves.

Spotted water hemlock (Cicuta maculata var. angustifolia) main leaflets of the middle and upper leaves are narrower, more than 5 times as long as wide. The fruit is almost globe-shaped, not oblong.

 
     
 
Habitat
 
 

Wet to moderate moisture. Meadows, woods, marshes.

 
     
 
Ecology
 
 

Flowering

 
 

June to August

 
     
 

Pests and Diseases

 
 

 

 
     
 

Toxicity

 
 

Spotted water hemlock is the most poisonous plant in Minnesota and may be the most poisonous plant in all of North America. All parts of the plants are toxic, but the tuberous roots, swollen lower stems, and all new growth are especially toxic.

 
     
 
Use
 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

4, 7, 24, 29, 30.

MNTAXA recognizes only one variety, var. maculata, in Minnesota, and shows all occurences of the species as belonging to that variety. The map at left does not include MNTAXA data.

 
  2/27/2023      
         
 

Nativity

 
 

Native

 
         
 

Occurrence

 
 

Very common

Of the three varieties of Cicuta maculata found in Minnesota, var. maculata is by far the most common.

 
         
 
Taxonomy
 
  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Asteranae  
 

Order

Apiales (carrots, ivies, and allies)  
  Suborder Apiineae  
 

Family

Apiaceae (carrot)  
  Subfamily Apioideae  
  Tribe Oenantheae  
 

Genus

Cicuta (water hemlocks)  
  Species Cicuta maculata (spotted water hemlock)  
       
 

Synonyms

 
 

Cicuta curtissii

Cicuta maculata var. curtissii

Cicuta mexicana

 
       
 

Common Names

 
 

common water hemlock

 

 

 

 

 

 

 

 

 

Glossary

Biternate

Twice ternate. A leaf divided into 3 segments, with each segment divided into 3 leaflets.

 

Bract

Modified leaf at the base of a flower stalk, flower cluster, or inflorescence.

 

Compound leaf

A leaf that is divided into leaflets, each leaflet having the general appearance of a leaf, with all leaflets attached to a single leaf stem.

 

Glaucous

Pale green or bluish gray due to a whitish, powdery or waxy film, as on a plum or a grape.

 

Mericarp

The split, usually one-seeded portion of a dry, multi-seeded fruit.

 

Node

The small swelling of the stem from which one or more leaves, branches, or buds originate.

 

Palmate

Similar to a hand. Having more than three lobes or leaflets that radiate from a single point at the base of the leaf.

 

Pinnate

On a compound leaf, having the leaflets arranged on opposite sides of a common stalk. On a bryophyte, having branches evenly arranged on opposite sides of a stem.

 

Sheath

The lower part of the leaf that surrounds the stem.

 

Ternate

Refers to leaves that are divided into three leaflets or sections.

 

Umbel

A flat-topped or convex, umbrella-shaped cluster of flowers or buds arising from more or less a single point.

 

Umbellet

A secondary umbel in a compound umbel.

 
 
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Luciearl

 
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Other Videos
 
  water hemlock / spotted water hemlock (Cicuta maculata syn. C. curtissii, C. mexicana)
UFInvasivePlantsEDU
 
   
 
About

Uploaded on May 20, 2010

Aquatic and Invasive Plant Identification Series by the UF/IFAS Center for Aquatic and Invasive Plants ( http://plants.ifas.ufl.edu ) and the Florida Fish and Wildlife Commission, Invasive Plant Management Section.

For more information about water hemlock, go to http://plants.ifas.ufl.edu/node/99

Video editor/videographer - Phil Chiocchio

   

 

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  Luciearl
7/23/2019

Location: Cass County

common water hemlock  
           
 
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