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Sonchus asper   (L. ) Hill
Riley County, Kansas
Height: 4-40 inches
Family: Asteraceae - Sunflower Family
Flowering Period:   June, July, August, September,October
Also Called: Prickly sowthistle.
Stems: Erect, branched in inflorescence.
Leaves: Alternate, stiff, obovate to ovate in outline, pinnately-divided to lobed or nearly entire, glabrous, margins wavy, with prickly spines, base clasping with rounded auricles; lower leaves 1.5 to 6 inches long, .4 to 3 inches wide; upper blades much reduced and less divided.
Inflorescences: Heads, 3-25 in corymb-like cluster, terminal; heads flask-shaped, 1/2 to 1 inch wide; phyllaries lanceolate to linear, 1/3 to 3/5 inch.
Flowers: Involcure up to 3/5 inch tall; florets 50-150, all ligulate, fertile; ligule shorter than corolla tube, corolla yellow.
Fruits: Achenes, flattened, about 1/10 inch long, 3-5 ribs on each face; pappus of white, hair-like bristles, 1/4 to 1/3 inch long.
Habitat: Moist disturbed sites, waste areas, gardens, roadsides, and cultivated fields.
Distribution: Principally in the east 1/2 of Kansas, but scattered west.
Origin: Introduced from Eurasia.
Comments: This weedy species can accumulate nitrates, but is rarely consumed by livestock. Latin asper means "rough or "prickly".

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