Edwards Plateau Greenthread

Thelesperma simplicifolium is used in roadside plantings and may be encountered as a waif outside its natural range in the flora area (e.g., in California).

Perennials or subshrubs (may flower first year), (20–)30–70+ cm. Cauline leaves ± scattered over proximal ³/4+ of plant heights, internodes mostly 45–95 mm; lobes mostly linear to filiform, sometimes oblanceolate, (5–)15–45(–60) × 0.5–1(–2) mm. Calyculi of 6–8+ linear to subulate bractlets 1–3+ mm. Ray florets usually 8, rarely 0; laminae yellow, 9–15(–20+) mm. Disc corollas yellow with red-brown nerves, throats equal to or longer than lobes. Cypselae 3–4 mm; pappi usually 0, rarely 0.1–0.3+ mm. 2n = 20.

Cosmidium simplicifolium A. Gray, Mem. Amer. Acad. Arts, n. s. 4: 86. 1849; Thelesperma curvicarpum Melchert