Eurybia sibirica |
Eurybia surculosa |
|
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arctic aster, Siberian aster, Siberian wood-aster |
creeping aster |
|
Habit | Plants (1–)5–60 cm; clonal and clumped, eglandular; rhizomes creeping to ascending, scaly, woody with age. | Plants 10–90 cm; in clones and clumps (sometimes with rosettes), eglandular (except pedicels); rhizomes slender, herbaceous becoming woody, scaly. |
Stems | 1–5+, usually ascending, sometimes decumbent, often purplish, sometimes branched basally, flexuous, proximally sparsely villous, distally usually densely villous, sometimes lanate. |
1–3+, erect, simple, straight, proximally sparsely strigillose to glabrescent, distally strigose or villoso- or hirsuto-strigose. |
Leaves | cauline (dark green abaxially, paler grayish green adaxially), firm, ± markedly veined, margins coarsely and sometimes irregularly serrate, sometimes (distal) serrulate or entire, villoso-ciliate, teeth mucronate, slightly incurved, apices obtuse to acute, mucronate, abaxial faces glabrescent to scabridulous, sparsely villous along veins, adaxial sparsely to ± densely villous or villoso-strigose; proximal winged-petiolate to sessile, petiole bases sheathing, blades spatulate, obovate to oblanceolate, or ovate (smaller than mid), 9–50 × 3–22 mm, bases attenuate to tapering and (in sessile) subclasping; mid short-petiolate to subpetiolate or sessile, blades lanceolate to lance-ovate, oblong to oblanceolate, or obovate to spatulate, 25–95 × 6–35 mm, gradually reduced distally, bases rounded or subauriculate to widely attenuate or cuneate; distal (arrays) sessile, lanceolate, lance-ovate, or elliptic to oblanceolate, 8–60 × 1–12 mm, rapidly reduced distally. |
basal and cauline, firm (only midnerves conspicuous), margins slightly revolute, slightly indurate, entire or sometimes remotely crenulate-serrulate, scabrous, teeth indurate, apices acute to obtuse, indurate, often mucronate, abaxial faces scabrous, adaxial sparsely strigose or glabrous; basal and proximal cauline usually persistent, sometimes withering by flowering (bases often marcescent), petioles sometimes narrowly winged, bases sheathing, blades narrowly elliptic, narrowly ovate, or lanceolate to spatulate, narrowly obovate, or oblanceolate, 13–135 × (2–)6–35 mm (earliest smaller), bases attenuate to cuneate; mid short-winged-petiolate or sessile, blades lance-oblong, lance-elliptic, lanceolate, or oblanceolate, 22–105 × 3–14 mm, gradually reduced distally, bases slightly auriculate-clasping to cuneate or attenuate; distal (arrays) sessile, blades lanceolate to linear, 7–42 × 1–6 mm, abruptly reduced. |
Peduncles | villous; bracts 0–3, sometimes immediately subtending heads, lanceolate or spatulate to linear-lanceolate, leaflike or phyllary-like distally (bases indurate, margins purplish), mostly foliaceous, villous. |
densely strigose or strigoso-hispid, sometimes sparsely long-stipitate-glandular distally; bracts (0–)1–3(–6), leaflike to phyllary-like (bases indurate), scabrous or sparsely strigose. |
Involucres | campanulate, 6–9 mm, shorter than pappi. |
cylindro-campanulate, 7–11(–13) mm, shorter than pappi. |
Ray florets | 12–50; corollas white to pale violet or purple, 7–17.5 × 0.8–1.8 mm. |
13–30; corollas bluish violet, (8–)11.5–15.5 × 1.5–2.3 mm. |
Disc florets | 25–125; corollas yellow becoming purplish, 5–8.1 mm, slightly ampliate, tubes longer than funnelform throats, lobes erect, triangular, 0.5–1.1 mm. |
25–40; corollas pale yellow turning purplish, 5–7.2 mm, slightly ampliate, tubes shorter than funnelform throats, lobes erect, deltate to triangular, 0.75–1.1 mm. |
Phyllaries | 30–80 in 3–4(–5) series, sometimes wholly purplish, usually ± oblong-lanceolate to oblanceolate, sometimes linear-lanceolate (innermost), subequal or ± unequal, membranous, bases indurate, ± rounded, dark green zones lanceolate or truncate at base, in distal 1/3–4/5+ (outer, often foliaceous, sometimes bractlike and surpassing involucres) to 1/4–2/3 (inner), margins hyaline, often purplish, narrowly scarious, erose, densely villoso-ciliate, apices squarrose, acute, apiculate, faces villous. |
35–65 in 4–5 series, oblong (outer) to linear-oblong or seldom linear (inner), strongly unequal, membranous, bases indurate, rounded (outer), dark green zones foliaceous, sometimes slightly dilated, in distal 1/3–1/2 (outer) to 1/8–1/7 or none and not reaching margins (inner), margins hyaline or sometimes purplish, narrowly scarious, erose, ciliate (scarious parts), ± scabrous (foliaceous parts), sometimes short-stipitate-glandular (innermost), apices spreading to squarrose, obtuse, often dilated (innermost), mucronulate (outer) or apiculate (inner), abaxial faces glabrous or strigillose, both scabrellous on foliaceous parts. |
Heads | 1–50, borne singly or in open corymbiform arrays. |
(1–)3–50(–122+), usually in open or dense, corymbiform arrays, seldom borne singly. |
Cypselae | brown, fusiform, compressed, 2.5–3.7 mm, ribs 7–10 (stramineous), faces strigillose; pappi of dark cinnamon or reddish tan (sometimes apically clavellate) bristles 5.5–7.5 mm, ± equaling disc corollas. |
brown, cylindro-obconic, slightly compressed, 3.2–3.5 mm, ribs 8–10, stramineous, strigillose; pappi of tawny-yellowish to pinkish bristles 5.2–7.1 mm, ± equaling disc corollas. |
2n | = 18. |
= 36. |
Eurybia sibirica |
Eurybia surculosa |
|
Phenology | Flowering summer. | Flowering summer–fall. |
Habitat | Disturbed, open, gravelly or sandy areas in boreal forest, wet meadows, open aspen and spruce woods, riparian thickets, sandy or gravelly stream flats, stream banks, lakeshores, bluffs, sand dunes, sandy places, subalpine and mountain meadows | Dry to wet, especially sandy soils, open, pinelands, oak-scrub, clearings, bogs, roadsides |
Elevation | 0–2200 m (0–7200 ft) | 200–1500 m (700–4900 ft) |
Distribution |
AK; ID; MT; AB; BC; NT; NU; YT; n Eurasia
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AL; CT; DE; GA; KY; MA; MD; NC; OH; SC; TN; VA
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Discussion | Eurybia sibirica is known from the northern Rocky Mountains and the northern Pacific Coast northward, becoming frequent in Alaska, Yukon, and in the boreal forest region of the continental Northwest Territories; it crosses into Siberia to reach Scandinavia (R. Elven 1989). In British Columbia, northern individuals belong to E. sibirica, not E. pygmaea (contra G. W. Douglas et al. 1998–2002, vol. 1), and southern specimens sometimes are E. merita. G. L. Nesom (1994b) recognized three varieties, two of which have been reported from North America (var. sibirica and var. gigantea). At present, however, given the great phenotypic plasticity of this species, it appears preferable not to recognize varieties, pending studies on the validity of these entities. Eurybia sibirica has often been confused at its southern range limit with E. merita, from which it differs by its often more low-cespitose habit (versus more erect habit, but smaller individuals may be similar in this respect), usually more serrate leaves (versus subserrate to nearly entire), and subequal, foliaceous, purplish phyllaries (versus unequal, non-foliaceous, purple-margined). At the southern end of its range, near the Canada–United States border, E. sibirica is usually found at higher elevations than its congener, there at its northern limit. Aster sibiricus forma albinus Lepage is merely a color variant of the species and is not recognized here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Eurybia surculosa is of conservation concern in Virginia and Alabama. It is often confused with E. compacta, its close relative from the coastal plains. In states where both are present, it is found only inland in the southern Appalachian Mountains and not on the coastal plains; its larger heads help to differentiate it from E. compacta. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 370. | FNA vol. 20, p. 377. |
Parent taxa | Asteraceae > tribe Astereae > Eurybia | Asteraceae > tribe Astereae > Eurybia |
Sibling taxa | ||
Synonyms | Aster sibiricus, Aster beringensis, Aster giganteus, Aster montanus, Aster montanus var. giganteus, Aster richardsonii, Aster richardsonii var. giganteus, Aster sibiricus subsp. richardsonii, Aster sibiricus var. giganteus, E. sibirica var. gigantea | Aster surculosus |
Name authority | (Linnaeus) G. L. Nesom: Phytologia 77: 261. (1995) | (Michaux) G. L. Nesom: Phytologia 77: 262. (1995) |
Web links |