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aster poilu, awl American-aster, frost aster, hairy aster, hairy white Oldfield aster, Oldfield or frost weed or white Oldfield or hairy or hairy white Oldfield aster, white heath aster

Nahanni aster

Habit Perennials cespitose, (5–)20–120(–150+) cm; with stout, branched caudices, sometimes long-rhizomatous. Perennials, 7–39 cm, cespitose; slender, woody, short-rhizomatous (rhizomes of season shallow- or deep-seated, not producing rosettes near parent stems).
Stems

1–5+, ascending to erect (straight, stout), glabrate to hirsuto-hispid or pilose, sometimes glabrous or hairy in lines (var. pringlei).

1, ascending to decumbent (slender, green to reddish brown), glabrate or sparsely short woolly-pilose in lines or zones, more densely so distally.

Leaves

thin, margins ciliate, apices acute to acuminate, mucronate, faces glabrous or ± hirsute (particularly on abaxial midveins);

basal withering by flowering (new vernal rosettes developing at flowering), petiolate to subpetiolate (petioles winged, ciliate, bases sheathing), blades oblanceolate or obovate to spatulate, 10–60 × 5–15 mm, bases attenuate, margins sparsely crenate-serrate (mostly apically), apices obtuse to rounded;

proximal cauline usually deciduous at flowering (often with axillary clusters of small leaves), petiolate or subpetiolate to subsessile (petioles narrowly to broadly winged, clasping), blades elliptic-oblanceolate or -oblong to linear-lanceolate or -oblanceolate, 40–102 × 5–25 mm, progressively reduced distally, bases attenuate to cuneate, ± clasping, margins entire to serrate, softly ciliate, apices attenuate, hyaline-spinulose;

distal sessile, blades lance-oblong to linear-lanceolate to linear or linear-oblanceolate or linear-subulate, 10–100 × 1–8 mm, progressively reduced distally, branch leaves abruptly smaller, bases cuneate, margins entire or serrulate.

(light green, abaxial sometimes becoming much darker) thin to firm, margins entire, scabrous, apices mucronulate, faces glabrous;

basal persistent or withering by flowering, petiolate, blades oblanceolate to short-spatulate, 10–130 × 2–8 mm, bases cuneate to attenuate, margins rarely sparsely serrulate, apices obtuse, faces glabrous;

proximal cauline persistent or withering by flowering, sessile, blades oblanceolate to linear lanceolate, 13–60 × 2–6 mm, bases ± clasping, apices acute;

distal sessile, blades linear to linear-lanceolate, 10–36 × 1–4 mm, reduced distally, bases subauriculate, subclasping to ± clasping.

Peduncles

5–30(–50) mm, progressively shorter distally, glabrous or densely hispid, bracts 7–25+, appressed to ascending, sometimes ± spreading, linear to subulate, glabrate, ciliate or not, mucronate to apiculate, ± grading into phyllaries.

10–70 mm, sparsely to moderately short-strigose, bracts 0–10, lanceolate, often foliaceous, reduced distally.

Involucres

campanulate to cylindro-campanulate, (2.5–)3.5–5.1(–6.5) mm.

cylindro-campanulate, 4.7–7.4 mm.

Ray florets

(10–)16–28(–38);

corollas usually white, rarely pinkish or bluish, laminae (4–)5.4–7.5(–11) × (0.4–)0.8–1.3(–1.7) mm.

15–41;

corollas white to pale rose, often becoming rose-violet, laminae 5–13 × 0.7–1.8 mm.

Disc florets

(13–)17–39(–67);

corollas light yellow becoming reddish purple or brown, (2.5–)3–4.1(–5.5) mm, tubes much shorter than narrowly funnelform throats, lobes lanceolate, (0.4–)0.6–0.8(–1) mm.

20–60;

corollas yellow turning reddish with age, 3.7–6.6 mm, tubes shorter than funnelform throats, lobes erect to spreading, lanceolate, 0.4–0.8 mm.

Phyllaries

in 4–6 series, appressed or slightly spreading, oblong-lanceolate (outer) to linear (innermost) , unequal (rarely subequal), bases indurate 1/2–3/5, margins hyaline, scarious, erose, ± ciliolate distally, green zones lanceolate to lance-rhombic, apices acute or acuminate, involute, spinulose, faces glabrous or sparsely hirsutulous.

in 3–4 series, outer spatulate, inner lanceolate, ± unequal to subequal, bases indurate, margins reddish, papery, erose-ciliate, green zones lanceolate, apices acute, faces glabrous.

Heads

in open, leafy, often pyramidal, paniculiform arrays, branches divaricate or branches 10 cm or less ascending, often arched and secund, sometimes racemiform.

usually borne singly or in open, paniculiform arrays (sometimes terminating lateral branches arising from decumbent stems or from proximal stem branches), branches few.

Cypselae

whitish or gray, oblong-obovoid, sometimes ± compressed, 1–1.5 × 0.5–0.7 mm, 4–6-nerved, faces sparsely strigillose;

pappi white, 3.5–4 mm.

tan (nerves stramineous), obovoid, compressed, 2–3 mm, 3–5-nerved, faces strigillose;

pappi white, 4–6.5 mm.

2n

= 16.

Symphyotrichum pilosum

Symphyotrichum nahanniense

Phenology Flowering Aug–Sep.
Habitat Stream banks near hot mineral springs
Elevation ± 1000 m (± 3300 ft)
Distribution
from FNA
AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; VA; VT; WI; WV; BC; NB; NS; ON; QC
[WildflowerSearch map]
[BONAP county map]
from FNA
NT
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

The ecology and cytogeography of Symphyotrichum pilosum were summarized by J. G. Chmielewski and J. C. Semple (2001b). The species is often confused with S. ericoides, which inhabits the same kinds of open, prairie-like habitats; the latter can be distinguished by its smaller heads and spine-tipped phyllary apices. Because of that, the name Aster ericoides has been misapplied often in floras and in the horticultural trade.

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

Of conservation concern.

Symphyotrichum nahanniense is known only from the South Nahanni River (Mackenzie Mountains), Nahanni National Park.

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

Key
1. Stems sparsely to densely hirsute; leaves pilose; various substrates
var. pilosum
1. Stems glabrous; leaves glabrous or glabrate; mainly on calcareous substrates
var. pringlei
Source FNA vol. 20, p. 511. FNA vol. 20, p. 523.
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. ontarionis, S. oolentangiense, S. parviceps, S. patens, S. phlogifolium, 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. 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. pilosum var. pilosum, S. pilosum var. pringlei
Synonyms Aster pilosus, Aster ericoides var. pilosus Aster nahanniensis
Name authority (Willdenow) G. L. Nesom: Phytologia 77: 289. (1995) (Cody) Semple: in J. C. Semple et al., Cult. Native Asters Ontario, 134. (2002)
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