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willow aster, willow-leaf American-aster, willowleaf aster

soft aster

Habit Perennials (10–)50–150(–200) cm, colonial; fleshy long-rhizomatous. Perennials, 30–60 cm, colonial; long-rhizomatous.
Stems

1, erect to ascending (stout, ± glaucous or reddish), glabrate to moderately hispidulous-hirsute (mostly in lines) distally.

1–5+, ascending to erect, densely puberulent to lanate, especially distally.

Leaves

thick, firm, margins often revolute, scabrous, apices mucronate, abaxial faces glabrous, vein areoles conspicuous, ± isodiametric, adaxial waxy, glabrate to strigose, ± scabrous (distal cauline with axillary leaf clusters, sometimes becoming branches);

basal withering by flowering, petiolate to subpetiolate (petioles winged, bases sheathing, ciliate), blades spatulate, 40–70 × 10–25 mm, bases attenuate, margins entire to shallowly serrate, apices rounded to obtuse;

proximal cauline withering by flowering, sessile (subpetiolate), blades elliptic or lanceolate to oblanceolate or linear-lanceolate, 40–100(–150) × 3–18 mm, progressively reduced distally, bases cuneate, often slightly rounded, apices acute to attenuate, callus-pointed, abaxial faces scabrellous, adaxial glabrous or ± puberulent;

distal sessile, blades ovate or elliptic-lanceolate to lanceolate or linear, 10–85 × 2–17 mm, progressively reduced distally, bases cuneate, margins entire, apices acute or obtuse, callus-pointed.

thin, margins entire, apices acute, faces densely lanate-puberulent;

basal often withering by flowering, subpetiolate, blades oblanceolate, 15–50 × 5–20 mm, bases cuneate, margins entire, apices acute, faces densely lanate;

proximal cauline sessile or subpetiolate, blades oblanceolate, 50–150 × 10–25 mm, bases slightly clasping, rarely auriculate;

distal sessile, blades lanceolate, 30–100 × 10–20 mm, reduced distally, bases tapered, ± auriculate, apices acute.

Peduncles

0.3–2 cm, ± pilose, bracts 5–12+, ascending or recurved-spreading, lance-elliptic to lanceolate or linear-lanceolate, foliaceous, distal closely subtending heads, not grading into phyllaries.

densely cinereous to lanate, bracts 0–3, lanceolate to narrowly ovate.

Involucres

campanulate, (4–)5–7(–8) mm.

campanulate, 7–9 mm.

Ray florets

(6–)20–35;

corollas pale blue-violet to lavender or rose-purple, rarely white, laminae 5–10(–12) × 1–1.7 mm.

20–35;

corollas violet, laminae 12–20 × 1–2 mm.

Disc florets

20–30(–35+);

corollas cream or light yellow turning pinkish purple, 4–6.5 mm, tubes shorter than narrowly funnelform throats, lobes lanceolate, 0.5–1.3 mm.

35–70;

corollas yellow, 5–6.5 mm, lobes triangular, 0.5–1 mm.

Phyllaries

in 4–6 series, appressed, oblong-lanceolate to linear (innermost) (outer sometimes ± foliaceous), unequal, bases indurate 1/2–3/4, margins scarious, erose, hyaline, sparsely ciliolate (often ciliate basally), green zones lanceolate to lance-rhombic, apices sometimes spreading, acute to acuminate, mucronate, often reddish purple apically, faces glabrous.

in 4–5(–6) series, squarrose, oblong to oblanceolate, unequal, bases of outer indurate less than 1/3, margins entire, green zones oblong-linear to oblanceolate, apices acute or obtuse (sometimes minutely mucronate), faces densely puberulent to lanate.

Heads

in ample, foliaceous, usually dense, paniculiform arrays, branches ascending to spreading, ± racemiform.

in corymbiform to paniculiform arrays, branches to 20 cm.

Cypselae

purple or stramineous with purple, obovoid, sometimes ± compressed, 1.5–2 mm, 4–5-nerved, faces thinly strigillose;

pappi white, 4–6.5 mm.

brown, cylindric to obovoid, not compressed, 2.5–3.5 mm, 4–5-nerved, faces hairy;

pappi whitish, 5–7 mm.

2n

= 32, 48, 64.

= 32.

Symphyotrichum praealtum

Symphyotrichum molle

Phenology Flowering Aug–Oct. Flowering Aug.
Habitat Wet, loamy soils, wet prairies or meadows, lake and stream shores, oak savannas, open woods or thickets, fields, moist banks, ditches, roadsides, recent clearings Dry montane meadows
Elevation 0–400+ m (0–1300+ ft) 2000–3000 m (6600–9800 ft)
Distribution
from FNA
AL; AR; CT; DC; DE; FL; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MO; MS; NE; NH; NJ; NY; OH; OK; PA; RI; SD; TN; TX; VA; WI; WV; ON; Mexico (Chihuahua, Coahuila, Nuevo Léon) [Introduced in Europe]
[WildflowerSearch map]
[BONAP county map]
from FNA
WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Symphyotrichum praealtum was reported by H. R. Hinds (2000) as a possible introduced, non-persisting ephemeral in New Brunswick. The species is introduced in central Europe, where it has been confused with S. lanceolatum (J. C. Semple et al. 2002). A. G. Jones (1989) reported hybridization with S. lanceolatum and S. firmum.

G. L. Nesom (1994b, 1997) and J. C. Semple et al. (2002) recognize several varieties within the species: var. praealtum [syn. Aster coerulescens de Candolle, A. praealtus var. coerulescens (de Candolle) A. G. Jones, A. praealtus var. imbricatior Wiegand] (2n = 32); var. angustior (Wiegand) G. L. Nesom (syn. A. praealtus var. angustior Wiegand) (2n = 64); var. nebraskense (Britton) G. L. Nesom (syn. A. praealtus var. nebraskensis Britton); var. subasperum (Lindley) G. L. Nesom [syn. A. praealtus var. subasper (Lindley) Wiegand, A. subasper Lindley]; and var. texicola (Wiegand) G. L. Nesom (syn. A. praealtus var. texicola Wiegand). Some of these varieties deserve recognition, but the validity of others needs confirmation.

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

Symphyotrichum molle is known only from the Big Horn Mountains of Wyoming. Because of its densely hairy leaves, stems, and involucres, it was compared by its author with S. jessicae, a narrow endemic of southeastern Washington and adjacent Idaho.

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

Source FNA vol. 20, p. 521. FNA vol. 20, p. 535.
Parent taxa Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Occidentales
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. 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. 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
Synonyms Aster praealtus, Aster salicifolius Aster mollis
Name authority (Poiret) G. L. Nesom: Phytologia 77: 289. (1995) (Rydberg) G. L. Nesom: Phytologia 77: 286. (1995)
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