Erect annual herb, (0.1)-0.2-0.5 m tall, usually branched only above to form inflorescence. Leaves hairy when young, becoming sparsely hairy or almost glabrous; lowermost leaves elliptic, longcuneate and apetiolate, serrate with 3-7 teeth on each side; mid cauline leaves oblanceolate to linearoblong, remotely dentate, (50)-60-120 × 4-15 mm; uppermost leaves smaller, lanceolate, amplexicaul, entire or few-toothed. Bracts subtending involucre 9-12, linear-lanceolate, 1.5-3 mm long. Involucre cylindric; involucral bracts 10-13, linear, (6)-7-8 mm long. Ray florets 8-11; ligules yellow, 1-2 mm long. Disc yellow, c. 4-5 mm diameter. Achenes subcylindric, slightly narrowed to apex, densely hairy only between ribs, 2.8-3.2 mm long.

Herba annua, erecta. Folia infima elliptica, longi-cuneata, serrata; folia medicaulina oblanceolata vel linearioblonga, remote dentata; folia summa lanceolata, amplexicaulia integra vel pauci-dentata. Bracteae supplementariae 9-12, lineari-lanceolatae. Involucri bracteae 10-13, (6.5)-7.0-8.0 mm longae. Ligulae 8-11, 1.5-2.0 mm longae. A S. lauto bracteis longioribus, radiis brevioribus, folii formaque differt; a S. carnuloso habitu erecto, involucre angusto, folii formaque differt.