spiny plumeless thistle
Family
AsteraceaeScientific Name
Carduus acanthoides
Other Common Names:
carduus thistle
plumeless thistle
Habit
Upright, growing from a taproot
Leaves
Leaves are arranged in a rosette at the base of the plant and alternate going up the stem. Leaf margins are serrate or pinnately lobed and leaves can be 4 to 8 in long and up to 3 in wide. Leaves are typically smooth on the underside.
Identifying Characteristics
This species is marked by spiny, winged stems. Overall, it is similar to musk thistle but typically differs in having smaller leaves and flowers and has an erect, winged peduncle.
Flower Seed Head
Flowers can be about an inch in diameter and exist alone at the end of a straight peduncle. Spiny bracts and a receptacle that is close to half the length of the flower characterize this species.
Seed Fruit
Achenes are flat ovals with a long pappus.
Where Found
This is common in disturbed areas like fields, roadsides, stream banks, and pastures.
Growth Habit
upright and nonwoody
Thorns or Spines
present
Approximate Flower Diameter
Varies:
dime,
nickle,
quarter
Dominant Flower Color
Varies:
purple,
pink
Flower Symmetry
radial symmetery
Leaf Hairs
Varies:
has hairs,
no hairs
Leaf Shape
Varies:
lance,
spatulate,
triangle
Leaf Arrangement
Varies:
alternate,
rosette
Leaf Margin
Varies:
lobed,
serrated
Leaf Structure
simple
Leaf Stalk
none
Stem Hairs
no hairs
Stem Cross Section
round or oval
Milky Sap
not present
Root Structure
taproot
Life Cycle
biennial
Ochrea
not present
Plant Type
Herb