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

Nahanni aster

Habit Perennials (10–)50–150(–200) cm, colonial; fleshy 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, erect to ascending (stout, ± glaucous or reddish), glabrate to moderately hispidulous-hirsute (mostly in lines) distally.

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

(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

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.

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

Involucres

campanulate, (4–)5–7(–8) mm.

cylindro-campanulate, 4.7–7.4 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.

15–41;

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

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

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

pappi white, 4–6.5 mm.

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

pappi white, 4–6.5 mm.

2n

= 32, 48, 64.

= 16.

Symphyotrichum praealtum

Symphyotrichum nahanniense

Phenology Flowering Aug–Oct. Flowering Aug–Sep.
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 Stream banks near hot mineral springs
Elevation 0–400+ m (0–1300+ ft) ± 1000 m (± 3300 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
NT
[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.)

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.)

Source FNA vol. 20, p. 521. 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. 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. 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
Synonyms Aster praealtus, Aster salicifolius Aster nahanniensis
Name authority (Poiret) 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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