Erigeron philadelphicus L.

Philadelphia Fleabane


CC = 3
CW = 0
MOC = 57

© SRTurner

Family - Asteraceae/Astereae

Habit - Biennial or perennial forb, with fibrous roots, occasionally producing short offsets at the end of the growing season, but not producing rhizomes or stolons.

Stems - Erect, 1 to several, to 80 cm long, usually sparsely to moderately branched above the lower 1/3, sparsely to moderately pubescent with mostly spreading hairs (the hairs sometimes more appressed toward the tip).

Erigeron_philadelphicus_stem.jpg Stem and node.

© DETenaglia

Erigeron_philadelphicus_roots.jpg Roots.

© DETenaglia

Leaves - Basal and alternate, simple. Basal leaves sometimes withered by flowering time, 2-15 cm long, sessile to short-petiolate, the blade narrowly oblanceolate to obovate, mostly long-tapered at the base, mostly rounded at the tip, the margins coarsely and bluntly to sharply toothed or scalloped, the surfaces and margins sparsely to moderately pubescent with short to long, spreading or loosely appressed hairs. Stem leaves usually relatively numerous, 1-10 cm long, sessile, the blade oblanceolate to lanceolate, angled or tapered to a usually sharply pointed tip, rounded to shallowly cordate and often slightly expanded at the base and more or less clasping the stem, the margins entire, scalloped, or with few to several sharp teeth on each side, these sometimes produced only from above the midpoint, the surfaces and margins sparsely to more commonly moderately hairy.

Erigeron_philadelphicus_basals.jpg Stem and lowermost stem leaves.

The wide leaf bases and auricles which clasp the stem somewhat are characteristic of this species.

© SRTurner

Erigeron_philadelphicus_leaf1.jpg Leaf adaxial.

© SRTurner

Erigeron_philadelphicus_leaf2.jpg Leaf abaxial.

© SRTurner

Erigeron_philadelphicus_leaves.jpg Pressed leaves.

© DETenaglia

Inflorescence - Rounded to more or less flat-topped panicles, usually open and often with numerous heads, usually bracteate.

Erigeron_philadelphicus_inflorescence2.jpg Inflorescence. The pink coloration is characteristic of new (recently opened) heads.

© SRTurner

Erigeron_philadelphicus_inflorescence.jpg Inflorescence.

© DETenaglia

Heads - Radiate. Involucre 4-6 mm long, the receptacle flat to convex, 6-15 mm in diameter at flowering, the bracts in one or two series, glabrous to moderately pubescent with more or less spreading hairs and sometimes also minutely glandular.

Erigeron_philadelphicus_heads2.jpg Freshly opened heads.

© SRTurner

Erigeron_philadelphicus_heads.jpg Flowering heads.

© SRTurner

Erigeron_philadelphicus_involucre.jpg Involucres.

© SRTurner

Florets - Ray florets 120-400, pistillate, the corolla 5-10 mm long, the ligule white or often pinkish when young. Disk to 1cm broad. Disc florets with the corolla 2.5-3.5 mm long, yellow at the apex, whitish basally. Pappus of the ray and disc florets similar, both with an inner series of (15-)20-30 threadlike bristles 1.2-3.2 mm long and an outer series of usually several shorter bristles or slender scales 0.1-0.4 mm long.

Erigeron_philadelphicus_flowers.jpg Florets.

© DETenaglia

Fruits - Achenes 0.6-1.2 mm long, sparsely and inconspicuously hairy.

Flowering - April - June.

Habitat - Streambanks, pond margins, bottomland and mesic forests, savannas, prairies, ledges and tops of bluffs, pastures, fields, gardens, cemeteries, railroads, roadsides, and open, disturbed areas.

Origin - Native to the U.S.

Lookalikes - Other species of Erigeron.

Other info. - This species has the most numerous ray flowers of any of Missouri's fleabanes. The stiffly spreading, threadlike ray ligules give the heads the appearance of miniature chimney sweep's brushes. It is not as common as the omnipresent E. annuus but is still easily found across much of the eastern and northern portions of the state. It occurs across most of the continental U.S. and Canada, though uncommon in the western Plains and mountain states. The plant is easily differentiated from other species of Erigeron by the main stem leaves, which are wide and clasping at their bases.

The common name "fleabane" is derived from an old belief that the plant repelled fleas. Native Americans used the plant medicinally as a cold remedy, analgesic, antidiarrheal agent, and a poultice for sores, and to reduce excessive bleeding following childbirth. It has also been used in herbal medicine for numerous ailments. Some people have a reaction to handling the plant.

Photographs taken at the Squaw Creek National Wildlife Refuge, 5-3-00, and in Brown Summit, NC., 4-29-03 (DETenaglia); also at Shaw Nature Reserve, Franklin County, MO, 5-23-2008, Weldon Spring Conservation Area, St. Charles County, MO, 5-10-2009, Riverfront Park, Washington, Franklin County, MO, 5-9-2018, and Katy Trail near Dutzow, Warren County, MO, 5-22-2020 (SRTurner).