poison hemlock
Family
ApiaceaeScientific Name
Conium maculatum
Other Common Names:
poison hemlock
poison parsely
Habit
Biennial or perennial erect growing herb. A basal rosette of leaves forms the first year followed by a tall branched stem the second year.
Leaves
Alternate and basal, triangular leaves that are 20-40 cm long and deeply lobed (almost like segments of the leaf). Leaflets are oval to oblong and hairless, with toothed margins. Petioles and stem are often spotted with purple. Lower leaves have a sheath that surrounds the stem. They are innately a compound.
Identifying Characteristics
There are distinctive purple spots located on the stem of poison-hemlock. It has a taproot.
Flower Seed Head
Small white flowers are formed in umbrella like clusters that are around 2 inches wide. Individual flowers are around 2-4 mm wide.
Seed Fruit
Fruit is a schizocarp containing two seeds. After maturity, the two sides break apart, and each half is rounded on one side and flat on the other with pale brown wavy ribs.
Where Found
It is common on roadsides and unmanaged areas, such as fence rows. It will infest areas where it is unprotected such as the center of a pasture. It does not tolerate mowing well.
Growth Habit
upright and nonwoody
Thorns or Spines
not present
Approximate Flower Diameter
pencil
Dominant Flower Color
white
Flower Symmetry
radial symmetery
Leaf Hairs
no hairs
Leaf Shape
triangle
Leaf Arrangement
Varies:
alternate,
rosette
Leaf Margin
Varies:
lobed,
serrated
Leaf Structure
pinnate
Leaf Stalk
shorter than leaf
Stem Hairs
no hairs
Stem Cross Section
Varies:
round or oval,
square or multi-edged
Milky Sap
not present
Root Structure
taproot
Life Cycle
biennial
Ochrea
Varies:
present,
not present
Plant Type
Herb