spiny sowthistle
Family
AsteraceaeScientific Name
Sonchus asper
Synonyms (former Scientific Names):
Sonchus nymanii
Leaves
Annual sowthistle is a summer annual plant which can grow up to 5 feet in height. It blooms from late spring through early fall and reproduces by means of seeds.
Identifying Characteristics
The parachute of the seeds has allowed for the wide spread dispersal of annual sowthistle. Among its defining characteristics are stiff, spined leaves which clasp at the stem.
Flower Seed Head
The flowers of annual sowthistle are yellow in color and approximately 1 inch in diameter. They bloom from late spring through early fall.
Seed Fruit
The seeds of annual sowthistle are, on average, 3 mm long and 2 mm wide. They are tan in color and have a small parachute of hairs which allows for easy dispersal.
Where Found
Annual sowthistle has spread throughout the majority of the United States. It is also present in many other countries, including in Europe and the rest of North America.
Growth Habit
upright and nonwoody
Thorns or Spines
present
Approximate Flower Diameter
Varies:
nickle,
quarter,
half dollar
Dominant Flower Color
yellow
Flower Symmetry
radial symmetery
Leaf Hairs
Varies:
has hairs,
no hairs
Leaf Shape
Varies:
oval,
spatulate
Leaf Arrangement
Varies:
alternate,
rosette
Leaf Margin
Varies:
entire,
lobed,
serrated
Leaf Structure
simple
Leaf Stalk
none
Stem Hairs
Varies:
has hairs,
no hairs
Stem Cross Section
round or oval
Milky Sap
present
Root Structure
Varies:
fibrous,
taproot
Life Cycle
summer annual
Ochrea
not present
Plant Type
Herb