Two-bristle rock daisy

Laphamia bisetosa Torrey ex A. Gray, Smithsonian Contr. Knowl. 5(6): 106. 1853

Perennials or subshrubs, 2–12 cm; glabrate, glabrous, minutely hairy, or scabrous-hispidulous. Leaves: petioles (0–)1–7 mm; blades lanceolate, lance-ovate, ovate, or suborbiculate, 4–8 × 2–8 mm, margins entire, serrate, or shallow-lobed. Heads usually borne singly (often obscured by the dense leaves), 7–8(–10) × 3.5–7 mm. Peduncles 0–3 mm. Involucres narrowly campanulate. Phyllaries 8–10(–12), linear to broadly or narrowly lanceolate, 4.5–6 × 1–2 mm. Ray florets 0. Disc florets 11–17; corollas white, tubes 0.8–1 mm, throats tubular to subfunnelform, 1.5–3 mm, lobes 0.8–1 mm. Cypselae oblong to oblanceolate, 1.8–2.2(–2.5) mm, margins notably calloused, glabrous; pap-pi of 2–3(–5) ± flattened bristles 1.5–2.3 mm.

Varieties 4 (3 in the flora): Texas; Mexico.