Symphyotrichum dumosum |
Symphyotrichum nahanniense |
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bushy American-aster, bushy aster, rice button aster |
Nahanni aster |
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Habit | Perennials, (20–)30–100 cm, colonial or cespitose; usually long-rhizomatous, often thick, woody, sometimes short, or with short, stout caudices. | Perennials, 7–39 cm, cespitose; slender, woody, short-rhizomatous (rhizomes of season shallow- or deep-seated, not producing rosettes near parent stems). |
Stems | 1–5+, erect (straight, often slender, brittle), densely or sparsely strigose to glabrescent or glabrate. |
1, ascending to decumbent (slender, green to reddish brown), glabrate or sparsely short woolly-pilose in lines or zones, more densely so distally. |
Leaves | firm, margins entire to crenulate-serrate, recurved, scabrous, apices sharply white-mucronate, abaxial faces glabrous or glabrate to sparsely strigillose, adaxial glabrous or glabrate to submarginally scabrous (short-strigose), cauline withering by flowering (except on array branches), often with axillary leaf clusters; basal withering by flowering, petiolate, petioles winged, sheathing, strigose-ciliate, blades oblanceolate to spatulate (often declined), 8–50 × 3–15 mm, bases attenuate to cuneate, margins crenate-serrate, apices obtuse or rounded to ± acute; proximal cauline (mostly declined) subpetiolate (petioles widely winged, clasping) or sessile (then not or barely clasping), blades linear-oblanceolate, 25–120 × 1.5–9 mm, bases cuneate to slightly attenuate; distal (ascending or spreading) sessile, blades oblong or linear-lanceolate to linear, 2–45 × 0.5–4 mm, reduced distally (abruptly on branches), bases cuneate to rounded, not clasping, margins entire or serrate. |
(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 | slender, usually stiff (sometimes lax), (0.5–)1–5 cm (rarely subsessile), progressively reduced distally, usually not secund, sparsely strigillose or glabrous, bracts 5–16+, spreading to ascending, linear-oblong or -elliptic to subulate or linear, progressively reduced distally, grading into phyllaries. |
10–70 mm, sparsely to moderately short-strigose, bracts 0–10, lanceolate, often foliaceous, reduced distally. |
Involucres | cylindro-campanulate, (3–)4.5–6.3 mm. |
cylindro-campanulate, 4.7–7.4 mm. |
Ray florets | 15–33; corollas pale blue, pink, or lavender to white, laminae (4–)5–7(–8) × 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 | 15–30; corollas cream to pale yellow turning pink, 3.5–4.5 mm, tubes shorter than to equal to narrowly funnelform throats, lobes lanceolate, (0.4–)0.6–1.1 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 or slightly spreading, oblong-oblanceolate (outer) to linear-oblanceolate or linear (innermost), strongly unequal, bases indurate (1/2–)2/3–4/5, margins hyaline, scarious, erose, distally ciliolate, green zones oblanceolate to elliptic (subapical), apices acute to obtuse (scarious), sometimes faintly reddish, mucronulate, faces usually glabrous, sometimes glabrate. |
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 remote, diffuse, open, paniculiform arrays, branches numerous, ascending to stiffly ascending, secondary ones stiff, racemiform (usually not secund). |
usually borne singly or in open, paniculiform arrays (sometimes terminating lateral branches arising from decumbent stems or from proximal stem branches), branches few. |
Cypselae | pink or stramineous with pink streaks, or gray (± dark, nerves stramineous), oblong-obovoid, sometimes ± compressed, 1.5–2.5 mm, 3–4-nerved (nerves prominent), faces strigillose; pappi white to sordid, 4 mm. |
tan (nerves stramineous), obovoid, compressed, 2–3 mm, 3–5-nerved, faces strigillose; pappi white, 4–6.5 mm. |
2n | = 16, 32. |
= 16. |
Symphyotrichum dumosum |
Symphyotrichum nahanniense |
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Phenology | Flowering Aug–Oct. | Flowering Aug–Sep. |
Habitat | Open or wooded, moist or wet soils, bogs, fens, sedge meadows, marshes, swamps, flood plains, sandy or calcareous flats, loamy prairies, old fields, sandhills, flatwoods, hammocks, pine-hickory woods, oak or pine thickets, secondary woods, sandy to mucky or marly shores of lakes and ponds, interdunal hollows | Stream banks near hot mineral springs |
Elevation | 0–700 m (0–2300 ft) | ± 1000 m (± 3300 ft) |
Distribution |
AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KY; LA; MA; MD; ME; MI; MO; MS; NC; NH; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; WI; WV; NB; ON
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NT |
Discussion | Symphyotrichum dumosum is introduced in New Brunswick. It is widely cultivated. It can hybridize with S. racemosum and S. lanceolatum var. interior (A. G. Jones 1989). G. L. Nesom (1994b) and J. C. Semple et al. (2002) recognized several varieties within the complex: var. dumosum [syn. Aster coridifolius Michaux, A. dumosus Linnaeus var. coridifolius (Michaux) Torrey & A. Gray]; var. gracilipes (Wiegand) G. L. Nesom (syn. A. dumosus var. gracilipes Wiegand); var. pergracile (Wiegand) G. L. Nesom (syn. A. dumosus var. pergracile Wiegand); var. strictior (Torrey & A. Gray) G. L. Nesom [syn. A. dumosus var. strictior Torrey & A. Gray, A. dumosus var. dodgei Fernald, S. dumosum var. dodgei (Fernald) G. L. Nesom, the latter possibly the hybrid S. dumosum × S. boreale fide G. L. Nesom 1997]; and var. subulifolium (Torrey & A. Gray) G. L. Nesom (syn. A. dumosus var. subulifolium Torrey & A. Gray). Some of these taxa may deserve higher rank. More work is needed in the complex, however, before a coherent taxonomy can be achieved. G. L. Nesom (1997) recognized also a southern pine flatwoods entity called Symphyotrichum kralii G. L. Nesom, based on the illegitimately named Aster pinifolius Alexander (not Nees, nor F. Mueller). The type of A. pinifolius, however, appears to be conspecific with that of S. simmondsii. At present, it seems best to wait for full investigation before formally recognizing such taxa. (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. 514. | 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 dumosus, Aster coridifolius | Aster nahanniensis |
Name authority | (Linnaeus) G. L. Nesom: Phytologia 77: 280. (1995) | (Cody) Semple: in J. C. Semple et al., Cult. Native Asters Ontario, 134. (2002) |
Web links |