Bolander’s water hemlock

(Cicuta maculata var. bolanderi)

Conservation Status


No image available

  IUCN Red List

not listed


N5 - Secure

SNR - Unranked


not listed

Wetland Indicator Status
  Great Plains

OBL - Obligate wetland


OBL - Obligate wetland

  Northcentral & Northeast

OBL - Obligate wetland


Bolander’s 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 much narrower than the space between the ribs. The lateral ribs are larger than the oil tube.

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




2 to 7


Flower Color




Similar Species


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

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

Common water hemlock (Cicuta maculata var. maculata) mericarp dorsal and intermediate ribs are as wide or wider than the space between the ribs. The lateral ribs are smaller than the oil tube.

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.


Wet to moderate moisture. Meadows, woods, marshes.




June to August




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.


Distribution Map











Uncommon in Minnesota

  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  


Apiales (carrots, ivies, and allies)  
  Suborder Apiineae  


Apiaceae (carrots)  
  Subfamily Apioideae  
  Tribe Oenantheae  


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



Cicuta bolanderi


Common Names


Bolander cicuta

Bolander’s water hemlock

common water hemlock


poison parsnip

spotted cowbane

spotted parsley

spotted waterhemlock

spotted water-hemlock













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



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.



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



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



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



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



Having the leaflets of a compound leaf arranged on opposite sides of a common stalk.



The lower part of the leaf that surrounds the stem.



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



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



A secondary umbel in a compound umbel.

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