(Linnaeus) Á. Löve & D. Löve, Taxon. 31: 359. 1982.
Purplestem or swamp or red-stemmed aster, aster ponceau
Linnaeus, Sp. Pl. 2: 875. 1753
(7—)100—250(—300) cm, cespitose; thickly short-rhizomatous or with stout, branched caudices, sometimes long-rhizomatous.
1—5+, erect (straight to distally flexuous, stout 5—11 mm diam., usually reddish purple), usually densely to sparsely hirsute or hispid, glabrescent, often proximally glabrate, sometimes glabrate.
(dark green, not crowded) thin, margins remotely serrate to sometimes entire, scabrous, apices acute or acuminate to subcaudate, mucronate, abaxial faces glabrate, ± densely pilose along midveins, adaxial glabrate to scabrous; basal withering by flowering, subpetiolate to petiolate (petioles ± winged, bases dilated, sheathing), blades spatulate to oblanceolate or lanceolate, 30—10+ × 3—20+ mm, bases attenuate to cuneate, margins remotely crenate-serrate to denticulate or entire, apices acute or acuminate to rounded; proximal cauline withering by flowering, petiolate to subpetiolate (petioles widely winged, bases auriculate, clasping), blades lanceolate or oblanceolate to oblong, elliptic or elliptic-oblong, (55—)70—200(—220) × 10—40 mm, usually progressively lengthened to mid, bases ± attenuate to cuneate or auriculate and clasping; distal sessile, blades oblanceolate or lanceolate to oblong or elliptic-oblong (sometimes nearly panduriform), 8—160 × 1—40 mm, progressively reduced distally, strongly so and linear in arrays, bases ± strongly auriculate, clasping, margins subentire or entire.
in open, paniculiform (often corymbiform-looking) arrays, branches widely spreading to ascending, sparsely to moderately leafy with ± large leaves.
0.2—3+ cm, ± hispid or hirsute to villous, bracts 0—3, lanceolate or linear-lanceolate to linear, distal often subtending heads.
campanulate, (6—)8—12(—15) mm.
in 4—6 series, oblanceolate-spatulate to linear, subequal, bases indurate
/ 5 —
/ 2 , margins not scarious (outer) to narrowly scarious, erose, hyaline, sparsely ciliolate, green zones linear-lanceolate, outer sometimes ± foliaceous, to linear (inner), apices ± spreading at tip when foliaceous, long-acuminate to caudate, mucronate to apiculate, sometimes purplish tinged, faces glabrous or ± hispid.
20—50(—60); corollas usually pale to dark blue, lavender or purple, seldom white or pink, laminae (7—)12—18(—21) × (0.9—)1.4—1.8 mm.
30—50 (—90); corollas yellow or cream becoming pink or purple, (4.1—)5—6.5 mm, tubes shorter than cylindro-funnelform limbs, lobes triangular, 0.4—1.1 mm.
purple or brown (nerves stramineous), oblanceoloid, ± falcate, compressed, (2—)2.5—3.5(—4) mm, 3—4-nerved (nerves prominent), faces glabrous or sparsely strigillose;
white, 3.8—6 mm.
Varieties 2 (2 in the flora): e North America.
is one of the widest ranging species in the genus, growing from the edges of the prairies to the Atlantic coast, and from the Gulf coast of Texas to southern Ungava Bay (northern Quebec).
Several taxa have been recognized within this variable species. Here, we segregate
as a distinct entity. The tall, pink-rayed
of the outer coastal plains is also distinctive, despite reports of hybrids with
where their ranges overlap (see G. L. Nesom 1997b). A recently described member of the complex,
, is an ultramafic endemic from North Carolina. Here, within
, we recognize two varieties, the variable and widespread var.
, and var.
from the inner Gulf coastal plains, following Nesom, who also offered a useful summary of the infraspecific taxonomy of the species.
Nesom, G. L. 1997b. The status of
(Asteraceae: Astereae), an endemic of the Gulf coastal plain. Phytologia 82: 300—315.