Perennials, often short-lived , 10–100 cm; fibrous- or taprooted, caudices woody, usually simple, stems sometimes rooting adventitiously. Stems erect to sprawling or decumbent (small leaf tufts in axils of larger leaves), sparsely strigose to glabrate, eglandular. Leaves basal (and proximal cauline withering by flowering) and cauline; cauline blades elliptic to obovate, mostly 10–40(–50) × 5–13 mm, usually relatively even-sized along stems, margins entire or with 1–2 distal pairs of acute, mucronulate teeth or lobes, faces sparsely and loosely strigose to hirsuto-villous, eglandular. Heads 1–5 (usually from branches distal to midstem). Involucres 2.5–3.5 × 7–10 mm. Phyllaries in 3–4 series, sparsely strigose to hirsuto-villous or glabrate, sometimes minutely glandular. Ray florets 45–80; corollas 5–8 mm, laminae not or slightly coiling, white, sometimes drying pinkish. Disc corollas 2–3.1 mm. Cypselae 1–1.4 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 15–27 bristles. 2n = 18, 27, 36 (from Mexico, Central America, South America).
"Sprawling perennial herbs usually forming dense clumps; stems numerous, decumbent to weakly erect, slender, usually branched, glabrate to sparsely pubescent. Leaves 1-4 x 0.1-l cm, linear to elliptic, entire to dentate or shallowly lobed, lower ones often oblanceolate and 3-lobed. Heads solitary, 1-1.5 cm in diameter; involucral bracts in 3 series, linear, 3-6 mm long; ray florets 75-100 or more per head, rays white, becoming pink with age, 9-10 mm long; disk florets numerous, corollas yellow. Achenes pale brown, ca. 1 mm long."
Isolectotype for Erigeron irazuense Greenm. Catalog Number: US 577966 Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany Verification Degree: Original publication and alleged type specimen examined Preparation: Pressed specimen Collector(s): H. F. Pittier Year Collected: 1900 Locality: Volcan Irazu, Costa Rica, Central America
Decumbent, branching, sparsely pubescent, perennial herb to 50 cm. Leaves subsessile; lamina up to 3 × 1.5 cm, 3-5-lobed, narrowly ovate, becoming smaller and narrower and less lobed above, sparsely pilose or glabrescent. Capitula c.8 mm wide, hemispheric. Phyllaries 4 mm, c. 2-seriate. Rays white, pink outside, up to 5 mm. Achenes 1-1.5 mm, ellipsoid, pilose. Pappus c. 2.5 mm.