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crooked-stem American-aster, crookedstem aster

Habit Perennials, 20–90(–120) cm, colonial; long-rhizomatous.
Stems

1(–3+), ascending to erect (usually flexuous, sometimes ± straight, sometimes stout, older often dark purple), glabrous proximally, moderately hirsute distally.

Leaves

thin, margins scabrous, apices mucronate, abaxial faces glabrous, midveins hispid to glabrate, adaxial scabrous;

basal withering by flowering, petiolate (petioles slender or slightly winged, bases reddish, dilated, sheathing, ciliate), blades obovate to oblanceolate, 15–70 × 10–20 mm, bases attenuate, margins crenate-serrate, apices acute to obtuse;

proximalmost cauline withering by flowering, proximal mostly persistent, petiolate to subpetiolate (petioles ± widely winged, bases dilated, strongly auriculate-clasping), blades ovate to lance-ovate or elliptic-lanceolate to oblanceolate, 80–160(–200) × 15–55 mm, progressively reduced distally, bases attenuate, margins sharply serrate (teeth mucronulate), apices acuminate to subcaudate;

distal subpetiolate or sessile (petioles broadly winged, auriculate-clasping), blades oblanceolate to lanceolate, sometimes panduriform, 7–90 × 2–25 mm, progressively reduced distally, more sharply so on branches, bases attenuate (petiolate) or ± cuneate to auriculate-clasping and slightly constricted above auricles (panduriform), margins serrate or entire.

Peduncles

(8–)10–40 mm, sparsely to densely hispid, bracts lanceolate to linear-lanceolate, 3–12 mm, somewhat grading into phyllaries.

Involucres

campanulate, 5–6 mm.

Ray florets

17–25(–30);

corollas usually lavender to blue, rarely white, laminae 7.5–12(–15) × 1–2 mm.

Disc florets

39–50(–65);

corollas cream colored or light yellow becoming purple or brown, 3.5–5 mm, tubes ± equaling campanulate to funnelform throats (thinly puberulent), lobes triangular, 0.5–1 mm.

Phyllaries

in 4–6 series, oblong-lanceolate or -oblanceolate, slightly constricted near middle (outer) to linear-lanceolate or linear (inner), ± unequal (flexible), bases indurate 1/5–1/2, margins ± narrowly hyaline, scarious, erose, sometimes ciliolate distally, green zones lanceolate to linear-lanceolate (inner), often distally foliaceous, sometimes outer ± entirely so, apices spreading to ± squarrose, acute to acuminate, mucronulate, abaxial faces sparsely hirsutulous to glabrate or glabrous, adaxial glabrous or sparsely hirsutulous.

Heads

in broad, ± flat, corymbo-paniculiform arrays, branches often purplish, divaricate to ascending, slender.

Cypselae

dull purple or stramineous with purple streaks or purplish-tinged, cylindro-oblanceoloid to obovoid, ± compressed, 2–3(–3.5) mm, 4–6-nerved, faces sparsely to moderately strigillose;

pappi sordid, 3.5–4.5 mm.

2n

= 32.

Symphyotrichum prenanthoides

Phenology Flowering Aug–Oct.
Habitat Moist or swampy grounds, woods, thickets, meadows, seeps, stream banks, roadsides
Elevation 100–1500 m (300–4900 ft)
Distribution
from FNA
CT; DC; DE; IA; IL; IN; KY; MA; MD; MI; MN; NC; NJ; NY; OH; PA; VA; WI; WV; ON
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Discussion

Symphyotrichum prenanthoides is of conservation concern in Canada and in a number of states.

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

Source FNA vol. 20, p. 527.
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. priceae, S. puniceum, S. pygmaeum, S. racemosum, 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 prenanthoides
Name authority (Muhlenberg ex Willdenow) G. L. Nesom: Phytologia 77: 290. (1995)
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