1.
Euthamia caroliniana
(Linnaeus) Greene ex Porter & Britton, Mem. Torrey Bot. Club. 5: 321. 1894.
Coastal plain goldentop
Erigeron carolinianus
Linnaeus, Sp. Pl. 2: 863. 1753 (as carolinianum);
Euthamia
galetorum
Greene;
E. media
Greene;
E. microcephala
Greene;
E. microphylla
Greene;
E. remota
Greene;
E. tenuifolia
(Pursh) Nuttall;
Solidago lanceolata
Linnaeus var.
minor
Michaux;
S. moseleyi
Fernald;
S. tenuifolia
Pursh;
S. tenuifolia
var.
pycnocephala
Fernald
Perennials,
25—100 cm.
Stems
(branched distal to midstems) glabrous or glabrate, not glaucous.
Leaves
deflexed to erect; blades 1—5-nerved, linear, 24—70 × 1—3 mm (to 6 mm wide in some Maine and Nova Scotia populations), lengths 7.7—42.2 times widths, abruptly reduced distally, lax- to firm-herbaceous, apices obtuse to long-acuminate, faces abundantly and prominently gland-dotted (34—86 dots per mm
2
), glabrous, glabrate, or scabro-hirtellous on midnerves.
Heads
pedunculate or glomerulate, usually in flat-topped or rounded arrays 10—40% of plant heights (often with multiple layers, proximal branches 0.5—1 times array heights).
Involucres
campanulate to turbinate, 3—4.7(—5.3) mm
. Phyllaries
usually green-tipped, outer ovate, inner oblong-linear, apices obtuse to acute.
Ray florets
7—17(—25).
Disc florets
3—22; corollas 3.3—4.8 mm.
2
n
= 18.
Flowering Aug—Dec. Open, moist to wet, sandy soils, lake shores and dunes; 0—100 m; N.S.; Ala., Conn., Del., Fla., Ga., Ill., Ind., La., Maine, Md., Mass., Mich., Miss., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Va., W.Va.
J. L. Reveal (1991c) determined that the types of
Erigeron carolinianus
and
Solidago tenuifolia
are conspecific.
Southern forms of
Euthamia caroliniana
tend to have fewer florets per head and narrower, more widely spreading (or even reflexed) leaves. E. L. Greene (1902) named these geographic variants (e.g.,
E. microcephala, E. microphylla
). Overlap occurs in all characters; taxa cannot be confidently separated.
Euthamia galetorum
has been considered an endemic restricted to lake shores in Nova Scotia (H. A. Gleason and A. Cronquist 1991; D. J. Sieren 1981). It has been collected from Cape Cod, Massachusetts, and southwestern Maine. Intermediates with
E. caroliniana
occur, and
E. galetorum
plants represent the endpoint of a morphologic cline. Most characters used to distinguish the two taxa are environmentally plastic and may not be genetically distinctive.
D. J. Sieren (1981) considered
Euthamia caroliniana
to be restricted to the Atlantic coastal plain. It occurs disjunctly in the southern Great Lakes region. Sieren considered the disjunct populations conspecific with
E. gymnospermoides
. H. A. Gleason and A. Cronquist (1991) called them
E. remota
Greene, related to
E. gymnospermoides
. The short disc corollas and involucres, narrow leaves, and production of axillary fascicles in some populations show clear relationship to
E. caroliniana
, from which disjunct plants cannot be reliably separated.
