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Symphyotrichum praealtum

(Willow Aster)

Overview

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Threatened

Threat status

Interesting Facts

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Common Names

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Common Names in English:

Willow Aster, Tall Aster, Veiny-Line Aster, Willow-Aster, Willow-Leaf Aster, Willowleaf Aster

Description

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Family Compositae

The largest family of flowering plants , the Compositae (Asteraceae), comprising about 1,100 genera and more than 20,000 species and characterized by many small flowers arranged in a head looking like a single flower and subtended by an involucre of bracts. A head may consist of both ray flowers and disk flowers, as in the sunflower, of disk flowers only, as in the burdock, or of ray flowers only, as in the dandelion.

Genus Symphyotrichum

Annuals or perennials , 2-200 cm (colonial or cespitose, usually ± strongly heterophyllous , usually eglandular , sometimes stipitate-glandular ; rhizomatous , with woody caudices, or taprooted). Stems ascending to erect , rarely vinelike, usually simple , sometimes branched distally, seldom proximally, usually hairy in decurrent lines at least distally, proximally often glabrous , sometimes hairy, sometimes stipitate-glandular distally. Leaves basal (sometimes persistent to flowering) and cauline; petiolate (often basal and proximal , sometimes distal, petioles often ± winged , clasping , ciliate ) or sessile; blades (often purplish abaxially, 1, sometimes to 3-nerved) cordate to elliptic , oblanceolate , or spatulate (basal), ovate , elliptic, lanceolate, oblanceolate, or linear (cauline, usually progressively, sometimes abruptly or little reduced distally), margins serrate, crenate , or entire, scabrous or ciliate, faces glabrous or hairy, sometimes stipitate-glandular. Heads radiate or disciform (sect. Conyzopsis), usually in paniculiform , sometimes in racemiform or subcorymbiform arrays, sometimes borne singly. Involucres cylindric or campanulate to hemispheric , 4-22 mm diam. Phyllaries 20-84 in (3-) 4-6(-9) series, 1(-3) -nerved (not keeled ), oblong-lanceolate or oblanceolate or spatulate (outer and mid) to linear (innermost), unequal to subequal , outer sometimes foliaceous , bases usually indurate , margins usually scarious , erose, hyaline or not, (apices usually with a well-defined green zone, sometimes ± foliaceous), faces glabrous or hairy, sometimes stipitate-glandular. Receptacles flat to slightly convex , pitted , epaleate. Ray florets (8-) 12-35(-75+) ; usually in 1 series, in 2-5 series, rarely in 4-5+ series in S. frondosum, pistillate , fertile ; corollas white, pink, blue, or purple (rays 0, peripheral pistillate florets in 2-5+ series, corollas lacking laminae in sect. Conyzopsis). Disc florets (7-) 15-50(-110), bisexual , fertile; corollas yellow to white, becoming purplish to reddish or pinkish at maturity, ± ampliate , tubes usually shorter than funnelform (cylindric in sect. Conyzopsis) throats , lobes 5, erect, spreading , or reflexed , deltate, triangular, or lanceolate; style-branch appendages lanceolate. Cypselae usually obovoid or obconic, sometimes fusiform , ± compressed , nerves (2-) 3-5(-10, sometimes dark-translucent), faces glabrous or strigillose , eglandular (sparsely stipitate-glandular in S. novae-angliae) ; pappi persistent, of (20-) 25-40(-55) white to brownish, ± equal, barbellate , apically attenuate bristles in 1(-3) series. x = 8, 7, 5, 13, 18, 21.

Species ca. 90 (77, including 1 hy: North America, Mexico, West Indies, Central America, South America, e Eurasia ; introduced in Europe.

The taxonomy followed here is based partly on G. L. Nesom (1994b, 1997), with the removal or addition of species based on molecular phylogenies (e.g. , J. C. Semple et al. 2002; L. Brouillet and S. Selliah 2005).

A. G. Jones (1980) and J. C. Semple and L. Brouillet (1980) proposed classifications of North American asters in which the group now segregated as Symphyotrichum was recognized at various levels. A morphologically based phylogenetic analysis of North American asters was done by Jones and D. A. Young (1983). They identified a group similar to the current Symphyotrichum, but did not segregate it from Aster. G. L. Nesom (1994b, 1997) segregated Symphyotrichum from Aster in a strict sense on a morphologic basis. This segregation was supported by the molecular phylogenetic analysis of R. D. Noyes and L. H. Rieseberg (1999), and confirmed by later data (Semple et al. 2002). Nesom (1994b) provided a summary of the literature on the taxonomy of North American asters.

As here circumscribed, Symphyotrichum excludes members of subtribe Symphyotrichinae with x = 9 (Almutaster, Ampelaster, and Canadanthus), as well as Psilactis (x = 9, 5). These taxa form a grade basal to Symphyotrichum in molecular phylogenies. The genus includes species with x = 8, 7, 5, 13, 18, and 21 (see G. A. Allen 1986), with disploidy to 4 from x = 5. G. L. Nesom (1994b) provided reference to chromosome counts in the genus, and J. C. Semple (1995) reviewed cytologic data. At the present time, karyologic evolution within the genus remains unresolved due to lack of phylogenetic resolution among subgenera and sections in molecular phylogenies. The most basal species appears to be the isolated S. chapmanii (n = 7), a taxon that was unusual in Eurybia (x = 9) on morphologic and cytologic grounds (Semple 1982). Section Conyzopsis also has x = 7; its karyotype is similar to that of x = 8 subg. Symphyotrichum where it is placed. Subgenera Virgulus and Astropolium both have x = 5 (and 4 in the former) ; their karyotypes differ and currently they do not group in molecular phylogenies. The n = 13, 18, and 21 entities of subg. Ascendentes are polyploids resulting from hybridization between members of subgenera Symphyotrichum and Virgulus in the western United States (Allen 1985, 1986).

Taxonomy of Symphyotrichum is difficult. Species are usually heterophyllous, some strongly so. Individuals in the spring , with basal rosettes, often have leaf shapes quite different from those with cauline leaves seen later in the season . Phyllary shape on first- and later-formed heads may differ. Individuals may vary considerably in plant size and array development depending upon growing conditions. The genetic diversity within each species also appears considerable. Often, plastic or genetic variation have been ascribed mistakenly to hybridization. Nonetheless, hybridization has played a significant role in the taxonomy and evolution of the genus.

J. C. Semple and R. A. Brammall (1982), G. L. Nesom (1994c, 1997) and J. Labrecque and L. Brouillet (1996), among others, discussed Symphyotrichum hybrids. In the x = 8 subg. Symphyotrichum, in particular, interspecific hybridization sometimes renders the taxonomy difficult. In general, sympatric species of the same or of different ploidy levels may produce viable hybrids (e.g., M. L. Dean and K . L. Chambers 1983). Triploid hybrids seem to be generally unviable. Diploid-tetraploid crosses may occur via the production of unreduced gametes in the diploids (Brouillet 1983). Hybridization has led to the evolution of allopolyploid species (e.g., G. A. Allen et al. 1983, Allen 1985, 1986). Allopolyploid species bridge the morphologic gap between diploid entities. In most cases, exact parentage is undetermined, and the placement of some species within sections remains tentative.

Some species have autopolyploid series; for instance the wide-ranging S. lanceolatum has 2n = 32, 40, 48, 56, and 64 (J. C. Semple et al. 1983). Odd levels are the result of inter-cytotype hybridization. The geographic distribution of cytotypes often follows patterns that are interpretable in a geo-historic context (e.g., Semple et al.; A. Legault and L. Brouillet 1989).

On the basis of morphology, cytology , and molecular data, Symphyotrichum is divided into four subgenera. At present, on molecular phylogenetic grounds, all but subg. Symphyotrichum appear to be monophyletic, the exception being the intersubgeneric allopolypoloid subg. Ascendentes. Sections within subg. Symphyotrichum may or may not be monophyletic; relationships among them are still ill-defined and it is not possible to separate morphologically the western sect. Occidentales from the mainly eastern sect. Symphyotrichum with the characters used here. Relationships of sect. Conyzopsis (x = 7) to the western Occidentales have been suggested (e.g., G. L. Nesom 1994b).[1]

Physical Description

Species Symphyotrichum praealtum

Perennials (10-) 50-150(-200) cm, colonial ; fleshy long-rhizomatous. Stems 1, erect to ascending (stout, ± glaucous or reddish), glabrate to moderately hispidulous-hirsute (mostly in lines ) 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. Heads in ample, foliaceous , usually dense, paniculiform arrays, branches ascending to spreading , ± racemiform . 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. Involucres campanulate , (4-) 5-7(-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. Ray florets (6-) 20-35; corollas pale blue-violet to lavender or rose-purple, rarely white, laminae 5-10(-12) × 1-1.7 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. 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. 2n = 32, 48, 64. [source]

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. [source]

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. [source]

Habit: Forb/herb

Flowers: Bloom Period: August, September, October. • Flower Color: magenta

Size/Age/Growth

Size: 12-18" tall.

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; 0-400+ m

Typically found at an altitude of 0 to 1,092 meters (0 to 3,583 feet).[2]

Biology

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Reproduction

Duration: Perennial

Growth

Sunlight: Sun Exposure: Full sun .

Moisture: Drought Tolerance: High

Temperature: Cold Hardiness: 7a, 7b, 8b, 9a, 9b. (map)

Taxonomy

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Synonyms

A. salicifolius Aiton 1789 • Aster praealtus Poiret in J. Lamarck Et Al. • Suppl. 1: 493. 1811

Notes

Publishing author : Wiegand Publication : Rhodora 35: 25 1933

Basionym author: (Britton)

Publishing author: Wiegand Publication: Rhodora 35: 26 1933

Publishing author: Wiegand. Publication: Rhodora 35: 24 1933

Publishing author: A.Gray Publication: Syn. Fl. N. Amer. 1, pt . 2: 189 1884

An accepted name in the RHS Horticultural Database.

Name Status: Accepted Name. Latest taxonomic scrutiny: 15-Mar-2000

Place of publication: Phytologia 77:289. 1995 ("1994")

Name verified on 16-Dec-2003 by ARS Systematic Botanists. Last updated: 11-May-2004

Similar Species

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Members of the genus Symphyotrichum

ZipcodeZoo has pages for 225 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them:

S. adnatum (Scaleleaf Aster) · S. anomalum (Manyray Aster) · S. anticostense (Anticosti Island Aster) · S. ascendens (Chile Aster) · S. bahamense (Bahaman Aster) · S. batesii (Bates' Aster) · S. boreale (Northern Bog Aster) · S. bracei (Brace's Aster) · S. campestre (Meadow Aster) · S. campestre var. bloomeri (Bloomer's Aster) · S. campestre var. campestre (Western Meadow Aster) · S. carolinianum (Climbing Carolina Aster) · S. chilense (Creeping Aster) · S. chilense var. chilense (Pacific Aster) · S. chilense var. invenustum (Pacific Aster) · S. chilense var. medium (Pacific Aster) · S. ciliatum (Alkali Rayless Aster) · S. ciliolatum (Aster) · S. columbianum (Columbian Aster) · S. concolor (Eastern Silver Aster) · S. cordifolium (Blue Heart-Leaved Aster) · S. cordifolium 'Little Carlow' (Blue Heart-Leaved Aster) · S. cordifolium 'Little Dorrit' (Blue Heart-Leaved Aster) · S. cordifolium 'Photograph' (Blue Heart-Leaved Aster) · S. cusickii (Cusick's Aster) · S. defoliatum (San Bernardino Aster) · S. depauperatum (Frost Aster) · S. divaricatum (Slender Aster) · S. divaricatum 'Snow Heron' (White Wood Aster) · S. drummondii (Arrow Aster) · S. drummondii var. drummondii (Drummond's Aster) · S. drummondii var. texanum (Drummonds Aster) · S. dumosum (Bushy Aster) · S. dumosum var. dumosum (Rice Button Aster) · S. dumosum var. gracilipes (Rice Button Aster) · S. dumosum var. pergracile (Rice Button Aster) · S. dumosum var. strictior (Rice Button Aster) · S. dumosum var. subulifolium (Rice Button Aster) · S. dumosum 'Alice Haslam' (Bushy Aster) · S. dumosum 'Apollo' (Bushy Aster) · S. dumosum 'Blue Lagoon' (Bushy Aster) · S. dumosum 'Rose Serenade' (Bushy Aster) · S. dumosum 'Sapphire' (Bushy Aster) · S. dumosum 'Wood's Blue' (Rice Button Aster) · S. dumosum 'Wood's Light Blue' (Bushy Aster) · S. dumosum 'Wood's Pink' (Bushy Aster) · S. dumosum 'Wood's Purple' (Bushy Aster) · S. eatonii (Aster) · S. elliotii (Elliott's Aster) · S. ericoides (Heath Aster) · S. ericoides var. ericoides (Health Aster) · S. ericoides var. ericoides (White Heath Aster) · S. ericoides var. ericoides'Schneegitter' (Schneegitter Health Aster) · S. ericoides var. pansum (Manyflowered Aster) · S. ericoides var. prostratum (White Heath Aster) · S. ericoides var. prostratum (Kuntze) Nesom (Tufted White Prairie Aster) · S. ericoides var. stricticaule (White Heath Aster) · S. ericoides 'Blue Star' (Heath Aster) · S. ericoides 'Golden Spray' (Heath Aster) · S. ericoides 'Monte Casino' (Heath Aster) · S. ericoides 'Pink Star' (Heath Aster) · S. ericoides 'Schneegitter' (Heath Aster) · S. ericoides 'Snow Flurry' (Heath Aster) · S. eulae (Aster) · S. expansum (Southwestern Annual Saltmarsh Aster) · S. falcatum (Cluster Aster) · S. falcatum var. commutatum (White Heath Aster) · S. falcatum var. crassulum (White Prairie Aster) · S. falcatum var. falcatum (White Prairie Aster) · S. fendleri (Fendler's Aster) · S. fendleri 'My Antonia' (Fendlers Aster) · S. firmum (Glossy-Leaved Aster) · S. foliaceum (Alpine Leafybract Aster) · S. foliaceum (DC.) Nesom var. parryi (D.C.Eat.) Nesom (Parry's Aster) · S. foliaceum var. apricum (Alpine Leafybract Aster) · S. foliaceum var. canbyi (Canby's Aster) · S. foliaceum var. foliaceum (Alpine Leafybract Aster) · S. foliaceum var. parryi (Parry's Aster) · S. fontinale (Florida Water Aster) · S. frondosum (Alkali Aster) · S. georgianum (Georgia Aster) · S. grandiflorum (Largeflower Aster) · S. gravesii (Graves' Aster) · S. greatae (Greata's Aster) · S. hallii (Hall's Aster) · S. hendersonii (Lyall Aster) · S. jessicae (Jessica's Aster) · S. kralii (Kral's Aster) · S. laeve (Smooth Aster) · S. laeve var. concinnum (Smooth Blue Aster) · S. laeve var. geyeri (Geyers Aster) · S. laeve var. laeve (Smooth Blue Aster) · S. laeve var. Laeve 'Bluebird' (Bluebird Smooth Blue Aster) · S. laeve var. purpuratum (Smooth Blue Aster) · S. laeve 'Bluebird' (Smooth Aster) · S. laeve 'Calliope' (Smooth Aster) · S. lanceolatum (White Panicle Aster) · S. lanceolatum var. hesperium (White Panicle Aster) · S. lanceolatum var. hirsuticaule (White Panicle Aster) · S. lanceolatum var. interior (White Panicle Aster)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal February 28, 2008:

Identifiers

Footnotes

  1. Luc Brouillet, John C. Semple, Geraldine A. Allen, Kenton L. Chambers, Scott D. Sundberg "Symphyotrichum". in Flora of North America Vol. 20 Page 3, 9, 12, 18, 458, 459, 461, 462, 465, 466,. Oxford University Press. Online at EFloras.org. [back]
  2. Mean = 243.220 meters (797.966 feet), Standard Deviation = 177.360 based on 512 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
Last Revised: 7/15/2012