Zion Fleabane

Perennials, 1.5–25 cm (becoming colonial); taprooted or fibrous-rooted, stoloniform branches persistent (1–3.5 cm), lignescent, bearing leaf tufts at tips, usually not retaining old leaf bases. Stems erect to ascending or decumbent, glabrous proximally, strigose on distal ¹ / 2 , minutely glandular near heads. Leaves basal (persistent) and cauline; basal blades oblanceolate to oblanceolate-spatulate, 50–760 × 1–11 mm, margins usually pinnately 3–5-lobed (sinuses reaching nearly to midveins), sometimes entire to dentate and mixed with lobed, faces glabrous or sparsely strigose, eglandular; cauline blades linear, gradually reduced distally, margins entire. Heads 1–4. Involucres 2–4.5 × 3.5–7 mm. Phyllaries in 3–5 series, moderately hirsute to hirtellous, minutely glandular. Ray florets 22–38(–46); corollas white, drying pink to lavender or blue, often with abaxial lilac midstripe, 4–7 mm, laminae not coiling or reflexing. Disc corollas 1.6–2.8 mm (throats slightly indurate and inflated). Cypselae 1–1.5 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 7–15(–19) (persistent) bristles.

Erigeron sionis is a North American species of flowering plant in the family Asteraceae known by the common name Zion fleabane. It has been found in the southwestern United States, only in southern Utah. Some of the populations are inside Zion National Park, after which the species is named.

Erigeron sionis grows in shallow soil in open woodlands dominated by pine, juniper, Douglas fir, maple, and oak. It is a perennial, colony-forming herb up to 25 cm (10 inches) tall, spreading by means of stolons running along the surface of the ground. The inflorescence generally contains 1-4 flower heads. Each head contains 22–46 white ray florets surrounding many yellow disc florets.

Varieties Erigeron sionis var. sionis Erigeron sionis var. trilobatus (Maguire ex Cronquist) S.L.Welsh