White Flowered Forbs

White Flowered Forbs
African rue
Broadleaved pepperweed
Field bindweed
Hary whitetop
Horehound
Lens-podded hoarycress
Onionweed
Oxeye daisy
Poison hemlock
White clover
White sweetclover
Whitetop

 

Poison Hemlock
Leucanthemum vulgare Lam. (Aster family, Asteraceae)
 

Description

Poison hemlock is a much branched, warm-season, biennial forb 5 to 8 feet tall; stems smooth, green to blue-green, hollow; stems usually spotted or streaked with red or purple on the lower half; large taproot, roots are long, forked, white to pale yellow and 1/2 to 3/4 inch in diameter; when crushed, the leaves and root emit a rank, unpleasant odor sometimes compared to that of parsnips or celery; extremely poisonous.

Leaves: Leaves are shiny green, finely pinnately divided 3 to 4 times; leaflets are segmented and 1/8 to 1/4 inch long; lower leaves on long stalks stem-clasping; upper leaves on short stalks.

Flowers: Flowers May to August; white flowers borne in many umbel-shaped clusters, each supported by a stalk; umbels 1-1/4 to 2 inches broad; flowers lack sepals.

Fruit: Fruit is small, about 1/8 inch long; contains 2 concave, light brown, ribbed seeds; prominent wavy ribs and absence of oil cells between the ribs are important characters for distinguishing this fruit from others of the same natural order of plants.

Habitat

Found on poorly drained soils, particularly near streams, ditches, and other surface water. It also appears on roadsides, edges of cultivated fields, and waste areas within elevations that generally range from 4,000 to 10,000 feet.

Propagation/Phenology

Reproduces by seed.

Comments

Native to the Mediterranean region; poisonous property occurs in all parts of the plant, including the large taproot. New Mexico Class B noxious weed.

Collage of images of Poison hemlock

 

 
Forest Service Shield
Invasive plants and weeds of the national forests and grasslands in the southwestern region
Poison hemlock flowering umbel Poison hemlock fruit Poison hemlock plant Poison hemlock spotted main stem