Symphyotrichum ericoides |
Symphyotrichum ×amethystinum |
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aster éricoïde, heath American-aster, heath-leaf aster, little gray aster, rayless alkali aster, tuft white prairie aster, white heath aster |
amethyst aster, aster, hybrid aster |
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Habit | Perennials, 20–80(–100) cm, colonial or cespitose, eglandular; branched rhizomatous, or with ± cormoid, branched, woody caudices. | Perennials, cespitose, 30–120 cm; with thick, woody, short-branched caudices at ends of fleshy rhizomes. | ||||
Stems | 1–3+, ascending to erect (grayish brown to brown), sparsely to densely hispido-strigose, sometimes glabrescent proximally. |
1–5+, erect (light brown to grayish brown), densely hispidulo-hirsute. |
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Leaves | usually all except rameal withered by flowering, (light grayish green) firm apices ± white-spine-tipped (often with clusters of smaller leaves in axils); basal sessile, blades (3-nerved) oblanceolate to oblong or spatulate, 10–50 × 10–25 mm, bases attenuate, margins usually entire, rarely remotely serrate, scabrous, apices rounded to obtuse, faces usually sparsely hairy, often glabrous; proximal cauline sessile, blades (1- or 3-nerved) linear to lanceolate or oblong, 10–40(–60) × 1.5–4(–7) mm, reduced distally, bases cuneate, coarsely ciliate, margins entire, coarsely ciliate, apices acute or obtuse, faces moderately to densely strigose or hirsute; distal sessile, blades oblong-ovate, 10–40 × 1.5–3.5 mm, abruptly reduced distally, bases cuneate, margins entire, apices acute, faces moderately to densely strigose. |
light green, thin to firm; basal withering by flowering, sessile, blades oblanceolate, 10–40 × 3–10 mm, attenuate, margins usually entire, rarely remotely serrate, piloso-ciliate, apices obtuse, rounded to mucronulate, faces sparsely to moderately strigose; proximal cauline sometimes persistent by flowering, sessile, blades linear or oblong to elliptic-oblanceolate, 40–60 × 3–10 mm, bases rounded or slightly clasping, margins entire, scabrous, apices acute to obtuse, faces ± copiously hirsute; distal sessile, blades oblanceolate, 15–45 × 2–3(–4.5) mm, progressively reduced distally, bases cuneate, margins entire, apices acute, white-spine-tipped, faces sparsely strigose. |
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Peduncles | 0.5–1(–2) cm or subsessile, densely hairy, bracts dense, linear to narrowly lanceolate, usually reflexed, sometime appressed to ascending, 1.5–5(–6) mm, densely hairy, grading into phyllaries. |
hispid, bracts 1–3+, oblong-lanceolate, 3–5 mm, not grading into phyllaries. |
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Involucres | cylindric to campanulate, 2.5–4.5(–5) mm. |
campanulate to hemispheric, 4–6 mm. |
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Ray florets | (8–)10–18(–20); corollas usually white, rarely pink or bluish, laminae 6–12(–20) × 0.7–1.2 mm. |
20–35; corollas azure blue to violet or lavender, laminae 5–10 × 0.6–1.2 mm. |
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Disc florets | 6–12(–20); corollas yellow becoming brown, 2.5–4 mm, throats narrowly funnelform, lobes triangular, 0.5–0.6 mm, glabrous. |
20–30+; corollas light yellow turning pinkish to purple, 3–4 mm, tubes ca. 1/2 narrowly funnelform throats, lobes triangular, 0.5–0.7 mm, glabrous. |
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Phyllaries | in 3–4 series, oblanceolate to ± spatulate, unequal, firm, bases (whitish to tan) ± indurate in proximal 1/2–2/3, margins hyaline, scabrous proximally, green zones diamond-shaped, in distal 1/2, apices spine-tipped, (outer) spreading to reflexed or squarrose, faces (outer) sparsely to densely hispid, scabroso-hirsute adaxially, (inner) glabrous. |
in 3–5 series, linear-lanceolate, ± unequal to subequal, bases ± indurate, margins hyaline proximally, outer distally hispido-scabrous, green zones diamond-shaped, restricted to distal 1/2–1/4, apices (outer) spreading to reflexed, acute, subspinulose, (inner) acuminate, purplish, faces (outer) scabroso-puberulent or strigose, eglandular, inner distally stipitate-glandular. |
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Heads | (1–200+) in paniculiform arrays, branches fastigiate or arrays often pyramidal, racemiform, secund, crowded. |
in ample, leafy, paniculiform arrays, branches ascending, sometimes secund (heads often crowded). |
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Cypselae | deep purple turning brown, obovoid to oblong-obovoid, ± falcate, not compressed, 1.2–2 × 0.4–0.6 mm, 7–9-nerved (faint), faces sericeous or densely strigillose; pappi whitish, 3–4 mm. |
dull purple or brown, obovoid, not compressed, 1.5–2 mm, 7–9-nerved, faces densely sericeous; pappi tan to tawny, sometimes rose to violet-tinged, 3.5–5.5 mm. |
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2n | = 10. |
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Symphyotrichum ericoides |
Symphyotrichum ×amethystinum |
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Phenology | Flowering Aug–Oct. | |||||
Habitat | Fields, prairies, disturbed grounds | |||||
Elevation | 200–400 m (700–1300 ft) | |||||
Distribution |
AR; AZ; CO; CT; DC; DE; IA; ID; IL; IN; KS; MA; MD; ME; MI; MN; MO; MS; MT; ND; NE; NJ; NM; NY; OH; OK; OR; PA; RI; SD; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NT; ON; QC; SK; n Mexico
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CO; CT; IA; IL; IN; KY; MA; MD; MN; MO; ND; NE; NJ; NY; PA; RI; VT; WA; WI; ON |
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Discussion | Varieties 2 (2 in the flora). Symphyotrichum ericoides resembles S. pilosum var. pilosum, which has larger heads, longer rays, and phyllaries that are not spine-tipped, though the revolute margins can make them appear so. Two subspecies and four weakly separated varieties of S. ericoides were recognized by A. G. Jones (1978). Tetraploids of var. ericoides on the eastern prairies can be difficult to distinguish from S. falcatum. A number of aster cultivars are sold under the name “Aster ericoides.” These are all derived from European garden plants and are either cultivars of S. dumosum, S. lateriflorum, S. pilosum, or S. racemosum, or hybrids involving one of those species and another taxon. The misapplication of the epithet ericoides dates back to the nineteenth century and has persisted in the horticultural literature. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Symphyotrichum ×amethystinum is the F1 hybrid between S. ericoides and S. novae-angliae, encountered sometimes throughout the area where the two parental species co-occur. It is morphologically intermediate; it has non-spiny, sparsely stipitate-glandular phyllaries and rose-violet rays in mid-sized heads. Forma leucerythros Bemis and forma leucos Bemis have been described within this hybrid and may represent recombinants or normal population color variants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 20, p. 494. | FNA vol. 20, p. 497. | ||||
Parent taxa | Asteraceae > tribe Astereae > Symphyotrichum > subg. Virgulus | Asteraceae > tribe Astereae > Symphyotrichum > subg. Virgulus | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Aster ericoides, Lasallea ericoides, Virgulus ericoides | Aster amethystinus, Virgulus ×amethystinus | ||||
Name authority | (Linnaeus) G. L. Nesom: Phytologia 77: 280. (1995) | (Nuttall) G. L. Nesom: Phytologia 77: 294. (1995) | ||||
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