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small white American-aster, small white or smooth white Oldfield aster, smooth white Oldfield aster

Habit Perennials, 30–90(–100) cm, colonial or cespitose; long-rhizomatous or with woody caudices.
Stems

1–3+, erect (straight), glabrous or glabrate.

Leaves

thin, margins often ± revolute, scabrous, apices mucronate to mucronulate, faces glabrous or abaxial minutely pilosulous, cauline with clusters of smaller leaves in most axils;

basal withering by flowering (new vernal rosettes often present), petiolate (petioles narrowly winged, sheathing, strigoso-ciliate), blades spatulate to oblanceolate, 5–40 × 5–15 mm, bases attenuate or cuneate to rounded, margins crenate-serrate, apices obtuse to acuminate;

proximal cauline withering by flowering, petiolate or subpetiolate (proximalmost) or sessile (petioles winged, sparsely long strigoso-ciliate), blades elliptic or elliptic-lanceolate to lanceolate or linear-lanceolate, 20–70 × 3–20 mm, progressively reduced distally, bases clasping, margins becoming short-ciliate distally;

distal (ascending or spreading) usually sessile, sometimes subpetiolate, blades linear-lanceolate to linear, 5–60+ × 1–8 mm, notably unequal in size, reduced distally, abruptly so on branches, bases cuneate to attenuate, margins serrulate or entire.

Peduncles

slender, 0.2–3+ cm or subsessile, hairy in lines, bracts 5–15, linear-elliptic to acicular, 1–2 mm, glabrous, grading into phyllaries.

Involucres

cylindric, (2.5–)3.5–4.5(–5.5) mm.

Ray florets

(12–)16–20;

corollas usually white, rarely pink, laminae 5–8 × 0.5–1.2 mm.

Disc florets

10–20(–25);

corollas cream or pale yellow becoming pink or red, (2.5–)3–4.5 mm, tubes shorter than narrowly funnelform throats, lobes recurved to erect, lanceolate, 0.5–1 mm.

Phyllaries

in 4–6 series, appressed or outer ± spreading, oblong-lanceolate to linear (innermost) , unequal, bases indurate 1/4–1/2, margins narrowly scarious, hyaline, ciliolate, green zones oblanceolate to linear-oblanceolate, apices acute to acuminate, mucronate, sometimes lightly purple-tinged, faces glabrous.

Heads

in diffuse, ± pyramidal, paniculiform arrays, branches ± lax, spreading horizontally or arching, racemiform, subtended by patent to reflexed branch leaves, often crowded but not (or barely) secund.

Cypselae

gray to tan, obovoid, ± compressed, 1–1.8 mm, 4–5-nerved (faint), faces sparsely strigillose or sericeus;

pappi white, 2.5–3.5 mm.

2n

= 16.

Symphyotrichum racemosum

Phenology Flowering Aug–Oct.
Habitat Moist to wet, often alluvial soils, often brackish, marshes, savannas, bogs, wet meadows, prairie swales, swamps, borders of swamps, open bottomwoods
Elevation 0–200 m (0–700 ft)
Distribution
from FNA
AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KY; LA; MA; MD; ME; MO; NC; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; VT; WV; NB; ON
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Discussion

Symphyotrichum racemosum is introduced in Canada. The species is cultivated commercially under the name Aster ericoides cv. ‘Spray’. A. G. Jones (1989) reported hybridization with S. dumosum, S. lateriflorum, S. lanceolatum var. interior, and S. ontarionis. The name Aster vimineus Lamarck has been misapplied to this taxon.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 20, p. 515.
Parent taxa Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum
Sibling taxa
S. adnatum, S. anomalum, S. anticostense, S. ascendens, S. boreale, S. bracteolatum, S. campestre, S. chapmanii, S. chilense, S. ciliatum, S. ciliolatum, S. concolor, S. cordifolium, S. cusickii, S. defoliatum, S. depauperatum, S. drummondii, S. dumosum, S. elliottii, S. ericoides, S. eulae, S. falcatum, S. fendleri, S. firmum, S. foliaceum, S. fontinale, S. frondosum, S. georgianum, S. grandiflorum, S. greatae, S. hallii, S. hendersonii, S. jessicae, S. laeve, S. lanceolatum, S. lateriflorum, S. laurentianum, S. lentum, S. molle, S. nahanniense, S. novae-angliae, S. novi-belgii, S. oblongifolium, S. ontarionis, S. oolentangiense, S. parviceps, S. patens, S. phlogifolium, S. pilosum, S. plumosum, S. porteri, S. potosinum, S. praealtum, S. pratense, S. prenanthoides, S. priceae, S. puniceum, S. pygmaeum, S. retroflexum, S. rhiannon, S. robynsianum, S. sericeum, S. shortii, S. simmondsii, S. spathulatum, S. subspicatum, S. subulatum, S. tenuifolium, S. tradescantii, S. turbinellum, S. undulatum, S. urophyllum, S. walteri, S. welshii, S. yukonense, S. ×amethystinum
Synonyms Aster racemosus, Aster brachypholis
Name authority (Elliott) G. L. Nesom: Phytologia 77: 290. (1995)
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