2. Erigeron philadelphicus L. (Philadelphia fleabane)
Pl. 233 a–c; Map
972
Plants biennial
or perennial (often relatively short-lived) herbs, with fibrous roots,
occasionally producing short offsets at the end of the growing season, but not
producing rhizomes or stolons. Stems 1 to several, 20–80(–150) 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). Basal leaves sometimes withered by flowering time, 2–15 cm
long, sessile to short-petiolate, the blade narrowly oblanceolate to
oblanceolate or less commonly obovate, mostly long-tapered at the base, mostly
rounded at the tip, the margins coarsely and bluntly to sharply toothed or
scalloped, rarely shallowly pinnately lobed, 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 elliptic or lanceolate (the lower leaves rarely obovate),
angled or tapered to a usually sharply pointed tip, rounded to shallowly
cordate 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. Inflorescences rounded to more or less
flat-topped panicles, usually open and often with numerous heads. Involucre 4–6
mm long, the receptacle 6–15 mm in diameter at flowering, the bracts glabrous
or more commonly sparsely to moderately pubescent with more or less spreading
hairs and sometimes also minutely glandular. Ray florets 120–400, the corolla 5–10
mm long. Disc florets with the corolla 2.5–3.5 mm long. 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. Fruits 0.6–1.2 mm long, sparsely
and inconspicuously hairy. 2n=18. April–June.
Scattered to
common nearly throughout the state, but uncommon or apparently absent from
western portions of the Ozark Division (U.S., Canada; introduced in Europe).
Banks of streams and rivers, margins of ponds and lakes, bottomland forests,
mesic upland forests, savannas, upland prairies, sand prairies, and ledges and
tops of bluffs; also pastures, old fields, fallow fields, gardens, cemeteries,
railroads, roadsides, and open, disturbed areas.
Some botanists
have attempted to subdivide E. philadelphicus by recognizing
morphological extremes, but none of the segregates in this very variable
species seems worthy of formal taxonomic recognition, and none of them appears
to occur in the wild in Missouri. For example, plants with the stem leaves
glabrous or nearly so have been called var. glaber J.K. Henry and var. provancheri
(Vict. & J. Rousseau) B. Boivin, whereas robust plants with relatively
large, slightly succulent leaves (similar to plants that grow under some garden
situations) have been called var. scaturicola (Fernald) Fernald (the
oldest epithet for this taxon is actually var. acaulescens, but Lunell’s
name was never formally transferred to E. philadelphicus). Cronquist
(1947c) attributed such unusual morphologies to extreme environmental
conditions, such as abundant moisture and nutrient-rich soils or dry, rocky
habitats. Morton (1988) made a somewhat stronger case for the recognition of
var. provancheri by studying plants grown in the greenhouse, but this
accounted only for a few populations in the northeastern United States and
Canada.
Native Americans
used this species medicinally as a cold remedy, analgesic, antidiarrheal agent,
and a poultice for sores, and to reduce excessive bleeding following childbirth
(Moerman, 1998).