Zigzag Silkgrass

Pityopsis flexuosa is known only from the vicinity of Tallahassee.

Perennials, 20–50 cm; rhizomes 1–5 cm. Stems 1–6, ascending, sometimes reddish brown, usually simple, flexuous, slender, moderately sericeous, glabrescent. Leaves: basal equaling or shorter than cauline, persistent through winter, withering by flowering; cauline spreading to ascending, sessile, blades linear-lanceolate, 30–70 × 3–7 mm, apices acute, faces moderately sericeous, glabrescent; distal slightly reduced. Heads 3–20 per stem, in corymbiform arrays. Peduncles sparsely bracteolate, 1–11 cm, tomentose, sparsely, minutely glandular; bracteoles reduced distally. Involucres narrowly campanulate, (7–)8–11 mm (equaling pappi). Phyllaries in 4–6 series, margins hyaline, sometimes reddish distally, fimbriate (midnerves pronounced), apices acute, faces sparsely pilose, eglandular or sparsely, minutely stipitate-glandular. Ray florets 9–13; laminae 5–8 mm. Disc florets 25–45; corollas 5.5–7 mm, tubes and proximal throats sparsely puberulent, lobes 0.5 mm, glabrous or glabrate. Cypselae fusiform, 3–4 mm, ribbed (dark between ribs), faces sparsely strigose; pappi: outer of linear scales 0.3–1 mm, inner of 30–50 bristles 5.5–7 mm. 2n = 18.

Chrysopsis flexuosa Nash, Bull. Torrey Bot. Club 23: 107. 1896; Heterotheca flexuosa (Nash) V. L. Harms