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aster du lac Ontario, bottomland aster, Ontario American-aster, Ontario aster

arrow-leaf American-aster, white arrowleaf aster, white arrowleaf or arrowleaf aster

Habit Perennials, 20–120 cm, colonial; long-rhizomatous. Perennials, 40–120(–200) cm, cespitose; short-rhizomatous or with stout, branched caudices.
Stems

1–(2–3), ascending to erect (straight), proximally glabrate, distally uniformly villous or hirsute, or glabrous (var. glabratum).

1–5+, erect (straight to slightly flexuous, brittle, sometimes stout), proximally glabrous or glabrate, distally sparsely pilose.

Leaves

thin, margins scabrous, apices mucronate, abaxial faces usually sparsely to densely strigose or strigillose, sometimes glabrous (var. glabrum), adaxial usually strigose or scabrous, sometimes glabrate or glabrous (var. glabrum);

basal withering by flowering, petiolate to subpetiolate (petioles narrowly winged, ciliate, bases sheathing), blades spatulate to oblanceolate-obovate, 10–40 × 5–10 mm, bases attenuate, margins crenate-serrate, apices acute to rounded;

proximalmost cauline usually withering by flowering, petiolate or sessile (petioles narrowly winged, ± clasping), blades ovate or lance-ovate to elliptic-lanceolate or oblanceolate, 20–80(–12) × 5–35 mm, progressively reduced distally, bases attenuate to cuneate, margins serrate (sometimes coarsely) to crenate-serrate, apices acute to acuminate or short-caudate;

distal sessile, blades elliptic-lanceolate to oblanceolate or lanceolate, (6–)10–80+ × 2–25 mm, progressively reduced distally, bases cuneate, margins entire to serrulate, apices acute to acuminate.

thin, margins usually shallowly, sometimes deeply serrate, rarely entire (distal), (piloso- to strigoso-)ciliate to scabrous (distal), apices mucronate, abaxial faces moderately pilose, ± densely so on midveins, adaxial glabrate to sparsely pilose or scabrous;

basal usually withering by flowering, sometimes persistent, long-petiolate (5–15 cm, petioles not or narrowly winged, sheathing), blades ovate to lance-ovate or lanceolate, 25–120 × 15–50 mm, bases usually shallowly, sometimes deeply, cordate to truncate or rounded, apices acute, sometimes rounded;

proximal cauline sometimes deciduous at flowering, winged-petiolate (petioles distally usually broader-winged, clasping), blades ovate to lanceolate, 50–120 × 20–50 mm, gradually reduced distally, bases usually truncate or rounded to attenuate, sometimes cordate, apices usually acute or acuminate, sometimes nearly caudate;

distal ± shortly winged-petiolate or sessile, blades lance-ovate or lanceolate to linear-lanceolate, 10–100 × 1–25 mm, reduced distally, bases attenuate to cuneate, margins entire to subentire, scabrous, apices acuminate to subcaudate.

Peduncles

subsessile or 2–10(–20) mm, ± pilose, bracts 1–5, linear-lanceolate, pilose, grading into phyllaries.

0.3–2 cm, sparsely pilosulous to glabrate, bracts many, ascending, linear to subulate, 2–4 mm, grading into phyllaries.

Involucres

campanulate, 3–5.5 mm.

cylindric, (4–)4.5–6(–7) mm.

Ray florets

(10–)15–26;

corollas usually white, rarely pinkish or light purple to blue, laminae 3.5–5.5(–8) × 0.5–1.5 mm.

8–15(–20);

corollas mostly white to pale pink or lilac or light blue, laminae 4.5–8(–10) × 0.8–1.5 mm.

Disc florets

12–25;

corollas cream or light yellow turning magenta or purple (ampliate), 2.5–4(–4.5) mm, tubes shorter than funnelform throats, lobes slightly spreading to reflexed, lanceolate, 0.7–1.1 mm.

(8–)10–15(–20);

corollas whitish to cream becoming pink, (3.5–)4–5 mm, tubes shorter than funnelform throats (with hairs), lobes lanceolate, 0.4–0.7 mm.

Phyllaries

in (3–)4–6 series, unequal, appressed or ± spreading, linear-obovate (outer) to oblong-lanceolate to linear (inner), bases indurate 1/3–3/4, margins narrowly scarious to apices, erose, hyaline, ciliate, green zones lanceolate, apices acute to acuminate, mucronulate, faces (outer) sparsely pilose or glabrous (var. glabratum), (inner) glabrous.

in 4–6 series, appressed or recurved-spreading, subulate (outer) to linear-lanceolate (inner), unequal, bases indurate 1/3–1/2+, margins scarious, hyaline, erose, sparsely ciliolate (mostly distally), green zones linear-lanceolate (outer) to linear (inner), apices long-acuminate to caudate, recurved, hyaline-mucronate to aristate, tips often purple, faces glabrous.

Heads

in ample, open, paniculiform arrays, branches ± ascending or divaricate to long-arching, ± secund.

(crowded) in dense, elongate, paniculiform arrays, branches stiffly ascending to erect (sometimes arched when long, peduncles then often secund), usually racemiform, sometimes paniculiform, leafy.

Cypselae

gray or tan, oblong-obovoid, sometimes ± compressed, 1.2–1.8(–2) mm, 3–5-nerved, faces strigillose;

pappi whitish to white, 3–3.5 mm.

tan to brown or dull purple (nerves stramineous), obovoid, ± compressed, 1.8–2.5 mm, 4–6-nerved, faces glabrous or glabrate or very sparsely strigillose;

pappi white or rose-tinged, 3–4 mm.

2n

= 16.

Symphyotrichum ontarionis

Symphyotrichum urophyllum

Phenology Flowering Aug–Oct.
Habitat Open, dry or mesic, sandy or loamy, sometimes rocky soils, limestone pavements, glades, ravines, open oak, sassafras, aspen, or pine woods, edges of woods, moist or dry, rocky bluffs, savanna, wooded banks, stabilized dunes, fields, roadsides, hedgerows, railroads
Elevation 40–300+ m (100–1000+ ft)
Distribution
from FNA
AL; IA; IL; IN; KS; KY; LA; MI; MN; MO; MS; NC; NE; NY; OK; PA; SD; TN; TX; VT; WI; ON; QC
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; FL; GA; IA; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NJ; NY; OH; OK; PA; SC; TN; VA; VT; WI; WV; ON
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

Symphyotrichum ontarionis is often confused with S. lateriflorum, from which it can be distinguished by its shorter disc corolla lobes and abaxial leaf faces either moderately to densely hairy or glabrous to glabrate (var. glabratum), and without hairs along midveins (as is typical of S. lateriflorum).

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

The name Aster sagittifolius Wedemeyer ex Willdenow has been misapplied to this taxon; our interpretation of the type of this entity concords with that of A. G. Jones (1980), i.e., that it is conspecific with the type of Symphyotrichum cordifolium or a garden hybrid involving the latter. Aster sagittifolius forma hirtellus (Lindley) Shinners is not recognized here.

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

Key
1. Abaxial leaf faces moderately to densely hairy
var. ontarionis
1. Abaxial leaf faces glabrous or glabrate
var. glabratum
Source FNA vol. 20, p. 518. FNA vol. 20, p. 506.
Parent taxa Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum 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. 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. 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
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. 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. walteri, S. welshii, S. yukonense, S. ×amethystinum
Subordinate taxa
S. ontarionis var. glabratum, S. ontarionis var. ontarionis
Synonyms Aster ontarionis, Aster missouriensis Aster urophyllus, Aster sagittifolius var. dissitiflorus
Name authority (Wiegand) G. L. Nesom: Phytologia 77: 287. (1995) (Lindley ex de Candolle) G. L. Nesom: Phytologia 77: 294. (1995)
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