Symphyotrichum praealtum |
Symphyotrichum nahanniense |
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willow aster, willow-leaf American-aster, willowleaf aster |
Nahanni aster |
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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 |
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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 |
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]
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NT |
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 | ||
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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