Symphyotrichum yukonense |
Symphyotrichum racemosum |
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Yukon aster |
small white American-aster, small white or smooth white Oldfield aster, smooth white Oldfield aster |
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Habit | Perennials cespitose or colonial, 5–30 cm; with short, erect, woody caudices from long, thin rhizomes. | Perennials, 30–90(–100) cm, colonial or cespitose; long-rhizomatous or with woody caudices. |
Stems | 1–8+, erect (purplish to brown, slender), villous, more densely so distally, distally moderately stipitate-glandular. |
1–3+, erect (straight), glabrous or glabrate. |
Leaves | (yellowish to dark green. |
thin, margins often ± revolute, scabrous, apices mucronate to mucronulate, faces glabrous or abaxial minutely pilosulous, cauline with clusters of smaller leaves in most axils; basal withering by flowering (new vernal rosettes often present), petiolate (petioles narrowly winged, sheathing, strigoso-ciliate), blades spatulate to oblanceolate, 5–40 × 5–15 mm, bases attenuate or cuneate to rounded, margins crenate-serrate, apices obtuse to acuminate; proximal cauline withering by flowering, petiolate or subpetiolate (proximalmost) or sessile (petioles winged, sparsely long strigoso-ciliate), blades elliptic or elliptic-lanceolate to lanceolate or linear-lanceolate, 20–70 × 3–20 mm, progressively reduced distally, bases clasping, margins becoming short-ciliate distally; distal (ascending or spreading) usually sessile, sometimes subpetiolate, blades linear-lanceolate to linear, 5–60+ × 1–8 mm, notably unequal in size, reduced distally, abruptly so on branches, bases cuneate to attenuate, margins serrulate or entire. |
Peduncles | ± densely short-villous, ± densely stipitate-glandular, bracts 1–3, foliaceous, reduced. |
slender, 0.2–3+ cm or subsessile, hairy in lines, bracts 5–15, linear-elliptic to acicular, 1–2 mm, glabrous, grading into phyllaries. |
Involucres | campanulate, 7–10 mm. |
cylindric, (2.5–)3.5–4.5(–5.5) mm. |
Ray florets | (8–)15–30; corollas purple to blue, laminae 5–11 × 0.5–2 mm. |
(12–)16–20; corollas usually white, rarely pink, laminae 5–8 × 0.5–1.2 mm. |
Disc florets | 16–38; corollas yellow becoming brown, 4–6.5 mm, lobes triangular, 0.4–0.8 mm. |
10–20(–25); corollas cream or pale yellow becoming pink or red, (2.5–)3–4.5 mm, tubes shorter than narrowly funnelform throats, lobes recurved to erect, lanceolate, 0.5–1 mm. |
Phyllaries | in 3–4(–5) series, linear-lanceolate, subequal, bases scarious, margins hyaline or purplish, scarious, erose, ciliate or short-stipitate-glandular, green zones herbaceous at least distally, often purplish to purple, apices long-acuminate, spreading to reflexed, faces ± densely villous (outer more so), ± densely stipitate-glandular. |
in 4–6 series, appressed or outer ± spreading, oblong-lanceolate to linear (innermost) , unequal, bases indurate 1/4–1/2, margins narrowly scarious, hyaline, ciliolate, green zones oblanceolate to linear-oblanceolate, apices acute to acuminate, mucronate, sometimes lightly purple-tinged, faces glabrous. |
Heads | usually borne singly, sometimes in open, corymbo-paniculiform arrays, branches ascending. |
in diffuse, ± pyramidal, paniculiform arrays, branches ± lax, spreading horizontally or arching, racemiform, subtended by patent to reflexed branch leaves, often crowded but not (or barely) secund. |
Cypselae | brown (sometimes purplish, nerves stramineous), narrowly obovoid, ± compressed, ca. 3 mm, 7–10-nerved, faces sparsely to moderately sericeo-strigose; pappi sordid (barb tips sometimes purplish-tinged), 3.5–4.8 mm. |
gray to tan, obovoid, ± compressed, 1–1.8 mm, 4–5-nerved (faint), faces sparsely strigillose or sericeus; pappi white, 2.5–3.5 mm. |
Midrib | purplish, often prominent) thin, reduced distally, margins entire; basal withering by flowering, winged-petiolate to subpetiolate (petioles ± sheathing), blades narrowly oblanceolate, 8–15 × 1–3 mm, bases attenuate, margins scabrous, apices obtuse to acute, faces glabrous or glabrate; proximal cauline often withering by flowering, sessile or subsessile, blades linear-oblanceolate, 20–70 × 1–4 mm, bases ± clasping, margins ciliate, apices acute, abaxial faces glabrous or midnerve ± sparsely villous, adaxial glabrous or sparsely villous, midnerves ± villous; distal sessile, blades linear-lanceolate, 10–30 × 1–2.5 mm, bases ± subclasping, ± rounded to subauriculate, margins sometimes stipitate-glandular, apices acute, mucronate or white-spinulose, faces glabrous or sparsely villous, short-stipitate-glandular. |
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2n | = 10. |
= 16. |
Symphyotrichum yukonense |
Symphyotrichum racemosum |
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Phenology | Flowering Jul–Aug. | Flowering Aug–Oct. |
Habitat | Mud flats, gravelly, stony or silty lakeshores, sometimes saline areas | Moist to wet, often alluvial soils, often brackish, marshes, savannas, bogs, wet meadows, prairie swales, swamps, borders of swamps, open bottomwoods |
Elevation | 300–1500 m (1000–4900 ft) | 0–200 m (0–700 ft) |
Distribution |
AK; NT; YT |
AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KY; LA; MA; MD; ME; MO; NC; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; VT; WV; NB; ON
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Discussion | Of conservation concern. Symphyotrichum yukonense is distributed disjunctly on the John River in the southern Brooks Range (Alaska), Lake Kluane (Yukon), and the Mackenzie Mountains and middle Mackenzie River (Northwest Territories). It appears closely related to S. pygmaeum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Symphyotrichum racemosum is introduced in Canada. The species is cultivated commercially under the name Aster ericoides cv. ‘Spray’. A. G. Jones (1989) reported hybridization with S. dumosum, S. lateriflorum, S. lanceolatum var. interior, and S. ontarionis. The name Aster vimineus Lamarck has been misapplied to this taxon. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 485. | FNA vol. 20, p. 515. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Aster yukonensis, Virgulus yukonensis | Aster racemosus, Aster brachypholis |
Name authority | (Cronquist) G. L. Nesom: Phytologia 77: 294. (1995) | (Elliott) G. L. Nesom: Phytologia 77: 290. (1995) |
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