Erigeron philadelphicus
Sp. Pl. 2: 863. 1753.
Annuals, biennials, or short-lived perennials, 4–80 cm; fibrous-rooted, caudices simple. Stems erect (green proximally, leafy to arrays), hirsuto-villous to villous proximally, loosely strigose to sparsely hirsute distally, minutely glandular. Leaves basal (persistent or withering by flowering) and cauline; basal blades oblanceolate to obovate, (15–)30–110(–150) × 10–25(–40) mm, margins shallowly crenate to coarsely serrate or pinnately lobed, faces sparsely hirsute to villous, eglandular; cauline blades oblong-oblanceolate to lanceolate, gradually reduced distally (bases clasping to auriculate-clasping). Heads (1–)3–35 usually in corymbiform arrays (ultimate branches arising near stem tips). Involucres 4–6 × 6–15 mm. Phyllaries in 2–3 series (sometimes basally connate), hirsuto-villous to sparsely hirsute or glabrous, sometimes minutely glandular. Ray florets 150–250(–400); corollas usually white, sometimes pinkish, 5–10 mm, laminae not coiling or tardily coiling. Disc corollas 2.1–3.2 mm. Cypselae 0.6–1.1 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 15–20(–30) bristles.
Distribution
North America, introduced worldwide in temperate areas as a weed.
Discussion
Varieties 3 (3 in the flora).
Selected References
None.
Lower Taxa
Key
| 1 | Cauline leaf faces sparsely hirsute to villous | Erigeron philadelphicus var. philadelphicus |
| 1 | Cauline leaf faces glabrous or glabrate | > 2 |
| 2 | Leaves of basal rosettes withering by flowering; salt marshes, British Columbia | Erigeron philadelphicus var. glaber |
| 2 | Leaves of basal rosettes persistent through flowering; crevices in shale or dolomite, usually beside rivers or lakes, Ontario, Quebec, New York, and Vermont | Erigeron philadelphicus var. provancheri |