Sonchus asper, Spiny Sowthistle
Scientific Name: Sonchus asper
Common Name: Spiny Sowthistle
Also Called: Perennial Sowthistle, Prickly Sow Thistle, Prickly Sow-thistle, Prickly Sowthistle, Sharp-fringed-Sowthistle, Sow-thistle, Spiny Sow-thistle and Spiny-leaf Sow Thistle (Spanish: Chinita, Cerraja, Hoiidkam iwaki)
Family: Asteraceae, Sunflower Family
Synonyms: (Sonchus nymanii)
Duration: Annual, taproot
Size: Up to 5 feet.
Growth Form: Forb/herb; erect, tall, basal leaves; branching above; stems mostly hairless (glabrous) emit milky sap when broken.
Leaves: Green or glaucous; shiny, 2 to 10 inches, hairless; alternate; basal rosettes, pinnately or deeply cut with lateral appendages; clasping lobes with soft spines on tips, blades recurved, sessile, margins also prickly.
Flower Color: Pale yellow; ray strap-shaped (ligulate) flowers only; heads small ½ to 1 inch, in clusters on open branches; flowering stalks (peduncle) bristly; fruit an achene in rounded white feathery heads; dandelion-like, wind driven seed dispersal.
Flowering Season: February to August or may bloom year around.
Elevation: Sea Level to 8,000 feet.
Habitat Preferences: Common, slightly moist areas, roadsides, disturbed areas andwaste areas, cultivated areas, gardens.
Recorded Range: Throughout most of North America, northern Baja California and northern, central and southern Mexico. Throughout most of Arizona.
U.S. Weed Information: Sonchus asper is listed in: Weeds of Kentucky and adjacent states: a field guide, Weeds of Nebraska and the Great Plains, Weeds of the United States and Canada, and Weeds of the West. Plants included here may become weedy or invasive.
Invasive/Noxious Weed Information: No data available.
Wetland Indicator: Sonchus asper is listed on the USDA 2012 National Wetland Plant List.
Threatened/Endangered Information: No data available.
Comments: An introduced European invasive naturalized throughout North America and Greenland. The basal rosette may be confused with thistles which do not have milky sap. Other plants with similar appearances include; Annual Sowthistle, Sonchus oleraceus which has pointed lobes that clasp the stem and is generally less prickly and Prickly Lettuce, Lactuca serriola which differs with spines on the midvein under the leaf.
In Southwest Desert Flora also see Prickly Lettuce, Lactuca serriola.
Native Americans cooked the tender leaves as greens, see species account from Native American Ethnobotany, University of Michigan, Dearborn.