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eastern silver American-aster, eastern silver aster, eastern silvery aster

aster boréal, northern bog aster, rush American-aster, rush aster, rush or slender white or northern bog aster, slender white aster

Habit Perennials, 30–80 cm, cespitose; with cormoid, woody caudices. Perennials (5.5–)13–85 cm, colonial; slender (0.6–2.8 mm diam.), long-rhizomatous (rhizomes of season shallow- or deep-seated, not producing rosettes near parent stems).
Stems

1–10+, ascending to erect (light to dark brown), glabrous or densely canescent distally.

1–3+, erect (straight, slender, often reddish to slightly glaucous proximally), glabrous.

Leaves

(green to graysih) soft to firm;

basal withering by flowering, sessile, blades (1–3-nerved) elliptic-lanceolate, 10–43 × 5–15 mm, bases attenuate, margins usually entire, rarely remotely serrate, piloso-ciliate, apices acute to obtuse, faces silvery silky-pilose to sparsely pilose;

proximal cauline withering by flowering, sessile, blades oblanceolate, 20–35 × 5–15 mm, bases rounded, subclasping, margins entire, scabrous to silky-pilose, apices acute to obtuse, cuspidate mucronate, faces ± densely silky;

distal sessile, blades usually oblong to lanceolate, rarely ovate, 9–15 × 1.8–5 mm, reduced distally, bases cuneate, margins entire, apices acute, mucronate, faces ± densely silky or sparsely strigose, sometimes glabrate (var. devestitum).

stiff, margins entire to sparsely subserrulate, revolute, scabrellous, apices mucronulate, sometimes with callous point, faces glabrous, abaxial midveins sometimes sparsely strigillose;

basal withering by flowering, subpetiolate to petiolate, petioles winged, base dilated, sheathing, eciliate, blades linear-oblanceolate to ovate or suborbiculate, 20–150 × 5–60 mm, bases attenuate, margins shallowly serrate or entire, apices obtuse to rounded;

proximal cauline withering by flowering, sessile or subpetiolate, petioles widely winged, bases strongly clasping, blades linear-lanceolate to linear, 15–90 × 2–12 mm, bases attenuate to cuneate or subauriculate, ± clasping, apices obtuse to acute;

distal sessile, blades linear-lanceolate (sometimes lanceolate) to linear, (40–)60–150 × 2–6(–8) mm, ± reduced distally, bases subauriculate, subclasping, margins entire or sometimes remotely serrulate, apices acute.

Peduncles

densely hairy, bracts becoming linear, grading into phyllaries.

0.5–5 cm, glabrous, bracts 1–3, remote, linear-lanceolate to linear, reduced distally, not grading into phyllaries (sometimes subtending heads).

Involucres

campanulate to narrowly campanulate, 5–7 mm.

cylindro-campanulate, (4–)5–8 mm.

Ray florets

8–12;

corollas rose-purple, rarely white, laminae 4–9 × 1–1.5 mm.

(15–)25–35(–41);

corollas white to often pale rose, pale purple or lavender, laminae (7–)10–15(–20) × 1.1–1.5 mm.

Disc florets

(9–)11–17(–21);

corollas pink turning purple, 4.5–6 mm, tubes shorter than narrowly funnelform throats (thinly puberulent), lobes triangular, 0.4–0.7 mm.

(15–)25–30(–40);

corollas cream or pale yellow becoming pink or brown purple, 3.7–6.6 mm, tubes shorter than funnelform throats, lobes triangular, 0.5–1 mm.

Phyllaries

in 3–5 series, appressed, lanceolate-oblong, strongly unequal, bases (tan) ± indurate, margins scarious proximally, green distally, green zones restricted to apex, obscured by hair, apices usually acute, sometimes acuminate, usually mucronate, sometimes subspinulose, faces ± densely silky.

in 4–5 series, usually appressed, rarely outer recurved, lanceolate or oblong-lanceolate (outer) to linear (innermost) ± unequal to sometimes subequal, bases indurate 1/3–1/2 (sometimes not indurate), margins scarious, erose, hyaline or tinged with reddish purple, sparsely ciliolate, green zones lanceolate to linear-lanceolate, apices acute to acuminate, mucronate to apiculate, often purple or reddish purple (particularly inner), faces glabrous.

Heads

in narrow, paniculiform (virgate) arrays (1–3(–5) per branch).

borne singly or in open, often lax, racemiform or paniculiform arrays, branches ascending, sparsely leafy.

Cypselae

obovoid, not compressed, 2.5–3.5 mm, 7–10-nerved, faces densely strigose;

pappi tan, (3.5–)4–6 mm.

yellowish tan or purple to brownish with purple streaks or grayish tan (nerves stramineous), obovoid, ± compressed, 0.6–2 mm, 3–5-nerved, faces sparsely strigillose;

pappi white, 2.7–6.4 mm.

2n

= 16, 32, 48, 64.

Symphyotrichum concolor

Symphyotrichum boreale

Phenology Flowering Aug–Oct.
Habitat Mostly calcareous areas, fens, marshes, bogs, open cedar-tamarack-spruce swamps, stream and pond margins, wet meadows, swales
Elevation 0–1500+ m (0–4900+ ft)
Distribution
from FNA
AL; DE; FL; GA; KY; LA; MA; MD; MS; NC; NJ; NY; RI; SC; TN; VA
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CO; IA; ID; IL; IN; MA; MI; MN; MT; ND; NE; NH; NJ; NY; OH; PA; SD; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; NT; NU; ON; PE; QC; SK; YT
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

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

Some of the western populations originally determined as Symphyotrichum boreale in western Wyoming and adjacent Montana are referable to S. welshii. Those of eastern Wyoming, Colorado, and the Black Hills are S. boreale. There is a gap between the ranges of the two species in Wyoming where neither occurs. Symphyotrichum ×longulum (E. Sheldon) G. L. Nesom (syn. Aster longulus E. Sheldon), reported from Minnesota, is the hybrid between S. boreale and S. puniceum var. puniceum.

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

Key
1. Distal cauline leaves and phyllaries moderately to densely silky; e United States
var. concolor
1. Distal cauline leaves and phyllaries glabrous or sparsely hispido-pilose; panhandle Florida
var. devestitum
Source FNA vol. 20, p. 492. FNA vol. 20, p. 522.
Parent taxa Asteraceae > tribe Astereae > Symphyotrichum > subg. Virgulus 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. 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. urophyllum, S. walteri, S. welshii, S. yukonense, S. ×amethystinum
S. adnatum, S. anomalum, S. anticostense, S. ascendens, 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. urophyllum, S. walteri, S. welshii, S. yukonense, S. ×amethystinum
Subordinate taxa
S. concolor var. concolor, S. concolor var. devestitum
Synonyms Aster concolor, Lasallea concolor, Virgulus concolor Aster laxifolius var. borealis, Aster borealis, Aster franklinianus, Aster junciformis
Name authority (Linnaeus) G. L. Nesom: Phytologia 77: 278. (1995) (Torrey & A. Gray) Á. Löve & D. Löve: Taxon 31: 358. (1982)
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