SafePlants

Wavyleaf Thistle (Cirsium undulatum)

Cirsium undulatum, commonly known as wavyleaf thistle or gray thistle, is a native thistle species found in North America. This plant belongs to the Asteraceae (Sunflower) family.

Taxonomy and Nomenclature

• Scientific Name: Cirsium undulatum (Nutt.) Spreng.
• Common Names: Wavyleaf thistle, gray thistle
• Family: Asteraceae (Sunflower family)
• Synonyms: Carduus undulatus, Cirsium undulatum var. undulatum

Distribution and Habitat

• Native to much of central and western North America.
• Very common throughout western and central North America.
• Prefers well-drained locations.
• Can grow in many different habitats.

Ecological Role

• It can become a weed of pasture and cropland.
• Listed as "Selected" for wavyleaf thistle in Invasive Species Most Unwanted.

Morphological Characteristics

• Erect stems, branched only in upper parts.
• Stems are stout, leafy, simple or sparingly branched, grooved, and white-woolly.
• Leaves are oblong, divided into wavy shallow lobes.
• Leaves are alternate, crowded, simple, usually pinnately lobed.
• Plants are erect with few branches.
• Stem and leaves are densely covered with matted white hair.
• Leaves are 4-12 inches long and deeply lobed.
• Perennial from simple taproot, sometimes creeping.
• Stems erect, branching, 1 to 3-1/2 feet tall, white wooly.

Life Cycle

• Habit: native biennial or perennial.
• The native wavy leaf thistle is a perennial, spreading by seed only.

Interactions with Other Organisms

• Flower-feeding scarab beetles, Euphoria kerni, feed on the flowers; this beetle is thought to be a bee mimic.
• Nectaring butterflies, bees, and wasps are attracted to the flowers.

Further Information

• Kansas Wildflowers and Grasses: http://www.kswildflower.org/flower_details.php
• Discover Life: Discover Life
• Wikimedia Commons