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aster à longues feuilles, longleaf aster, Robyns' aster

Porter's or smooth white aster, smooth white aster

Habit Perennials, 10–80 cm, colonial; long-rhizomatous. Perennials, 10–50 cm, cespitose; usually with branched caudices, sometimes long-rhizomatous.
Stems

1, erect (± flexuous, often reddish), glabrous, hairy in lines distally.

1–4+, ascending to erect (straight), glabrous.

Leaves

stiff, margins sparsely serrulate or entire, ± revolute, scabrous, apices acute to acuminate, mucronulate, faces glabrous, sometimes midveins hairy;

basal withering by flowering, long-petiolate, petioles narrowly winged, bases sheathing, blades lanceolate, ca. 20 × 3–5 mm, slightly attenuate to narrowly cuneate;

proximal cauline withering by flowering, sessile or subpetiolate, blades linear-lanceolate to -oblanceolate, 100–200 × 4–8 mm, bases cuneate to attenuate, clasping;

distal sessile, blades linear-lanceolate to linear, 10–110 × 1–7 mm, progressively reduced distally, bases cuneate to rounded, slightly clasping or not, margins entire.

thin, margins usually entire, sometimes very sparsely serrulate distally, scabrous, apices acute, mucronulate, faces glabrous;

basal usually deciduous at flowering (new winter rosettes developed by flowering), petiolate (petioles narrow or ± winged, then appearing sessile, slightly sheathing, ciliate), blades oblanceolate to obovate or spatulate, 5–45+ × 2–6 mm, cuneate, apices obtuse;

proximal cauline usually withering by flowering, petiolate or sessile (petioles winged, slightly clasping, ciliate), blades oblanceolate or lanceolate to linear-oblanceolate or -lanceolate, 40–80(–90) × 2–5(–6) mm, bases cuneate;

distal sessile, blades linear-lanceolate to linear, ± falcate, 8–60 × 0.5–3 mm, reduced distally, bases cuneate to rounded-cuneate.

Peduncles

glabrous or ± densely pilose in lines, bracts 1–4, linear, sometimes inrolled distally, clasping, ciliate, distal 1–2 often subtending and surpassing involucres.

0.2–2.8 cm, bracteate, glabrous, bracts 1–3, linear to linear-lanceolate.

Involucres

campanulate, 5–8.5 mm.

campanulate to cylindro-campanulate, 3.6–5(–6) mm.

Ray florets

20–35;

corollas dark blue-violet, seldom white, laminae 8–13 × 1–1.5 mm.

(12–)20–34(–42);

corollas usually white, seldom pinkish, laminae 6.8–12 × 0.7–1.8 mm.

Disc florets

(18–)23–40;

corollas yellow, 4–6.5 mm, tubes shorter than funnelform throats, lobes lanceolate, 0.8–1 mm.

(30–)40–75(–103);

corollas pale yellow becoming pink and later brown, (2.8–)3.1–3.9(–4.9) mm, tubes much shorter than narrowly funnelform throats, lobes triangular, (0.3–)0.5–0.7(–0.8) mm.

Phyllaries

in 3–4 series, oblong-lanceolate, subequal, bases indurate 1/3–3/4, margins scarious, erose, hyaline, ciliate proximally, sparsely ciliolate distally, green zones lanceolate to linear, sometimes outer ± foliaceous, apices acuminate to long-acuminate, often foliaceous, mucronate to apiculate, faces glabrous, eglandular.

in 4–6 series, linear-lanceolate to -oblanceolate (outer) or oblong-lanceolate (inner), unequal, bases indurate 1/4–3/4 (sometimes outermost foliaceous), margins proximally narrowly scarious, erose, hyaline, distally ciliolate, green zones lanceolate, apices acute, ± spreading, involute, mucronulate, faces glabrous.

Heads

in elongate, open, narrow, paniculiform or racemiform arrays, branches ascending, short, leafy, branch leaves smaller and reduced distally (heads 1–3 per branch).

in paniculiform arrays, branches ascending, ± densely leafy with narrow branch leaves.

Cypselae

tan, obovoid, compressed, ca. 2.2–2.4 mm, 5–6-nerved, faces sparsely strigillose;

pappi pinkish, 7–8 mm.

purple to stramineous, obovoid to oblanceoloid, compressed, 1–2 mm, 4–5-nerved, faces sparsely, finely strigillose;

pappi white, 1.2–3.5 mm.

2n

= 64, 80.

= 16.

Symphyotrichum robynsianum

Symphyotrichum porteri

Phenology Flowering Aug–Sep. Flowering late Jul–Sep.
Habitat Wet or damp, open, sandy, gravelly, or rocky grounds, often calcareous, cracks in rocky stream or lake shores, limestone alvars, seasonally wet glades and swales, jackpine outwash plains Lower montane
Elevation 10–400 m (0–1300 ft) 1800–2900 m (5900–9500 ft)
Distribution
from FNA
MI; MN; WI; MB; ON; QC
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; NM; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

The name Aster longifolius Lamarck has been misapplied to this taxon.

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

Symphyotrichum porteri is the only western member of subsect. Porteriana; it grows in the foothills of the Rocky Mountains.

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

Source FNA vol. 20, p. 530. FNA vol. 20, p. 513.
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. 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. 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. 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
Synonyms Aster robynsianus Aster porteri, Aster ericoides var. strictus
Name authority (J. Rousseau) Brouillet & Labrecque: Phytologia 82: 138. (1997) (A. Gray) G. L. Nesom: Phytologia 77: 289. (1995)
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