1b. ssp. uliginosus (M. Bieb.) Nyman

S. arvensis var. glabrescens Günther, Grab. & Wimm.

Branches of the inflorescence glabrous or occasionally sparsely to densely pubescent with minute, branched, cobwebby to woolly hairs toward the tip, lacking gland-tipped hairs. Involucre glabrous or occasionally sparsely to densely pubescent with minute, branched, cobwebby to woolly hairs toward the base, lacking gland-tipped hairs. 2n=36. July–October.

Introduced, uncommon, known thus far only from Marion and St. Louis Counties and the city of St. Louis (native of Europe, introduced widely in North America). Railroads, gardens, and disturbed areas.