Eurybia sibirica
Eurybia radulina
arctic aster, Siberian aster, Siberian wood-aster
rough-leaf aster, rough-leaf wood-aster
1–5+, usually ascending, sometimes decumbent, often purplish, sometimes branched basally, flexuous, proximally sparsely villous, distally usually densely villous, sometimes lanate.
1–3, ascending to erect, often purple, simple, flexuous, proximally glabrescent or sparsely villous, distally ± densely villous.
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.
cauline, firm, margins slightly revolute, coarsely serrate or (distal) entire, scabrous to strigoso-ciliate, teeth mucronate, ± markedly veined, apices mucronate, abaxial faces scabrous, adaxial scabroso-strigose;
proximal mostly withering by flowering, petioles winged, shorter than blades, bases clasping, blades elliptic to obovate 12–45+ × 7–20+ mm, smaller than mid, apices obtuse;
mid narrowly winged-petiolate (petioles short with ± clasping bases), distally subpetiolate or sessile, blades ovate or elliptic to broadly oblanceolate or obovate, 32–85(–130) × 4–40 mm, gradually reduced distally, bases usually attenuate, sometimes cuneate, apices obtuse to acute;
distal (arrays) oblanceolate to lanceolate, 5–28 × 1–8 mm, more sharply reduced.
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 villous;
bracts 0–1, scabroso-strigose.
campanulate, 6–9 mm, shorter than pappi.
campanulate, 6–9 mm, shorter than pappi.
12–50;
corollas white to pale violet or purple, 7–17.5 × 0.8–1.8 mm.
10–15;
corollas white to sometimes pale violet or purple, 8.5–11(–13) × 1.3–2.3 mm.
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.
30–70;
corollas yellow becoming purple- or pinkish-tinged, 6–7(–8) mm, ± ampliate, tubes equaling to longer than funnelform-campanulate throats, lobes usually erect, sometimes ± spreading, lanceolate, 1–1.3 mm.
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.
38–62 in 4–5 series, midnerves slightly raised (outer), oblong (outer) to lanceolate-linear or linear (inner), unequal, membranous, bases indurate, ± rounded, green zones to scarious margins in distal 1/3–1/2 (outer; seldom ± wholly foliaceous) to 1/5 or none (inner), margins often purple, hyaline, narrowly scarious, erose, densely villoso-ciliate, apices appressed, sometimes purplish-tinged, usually acute, sometimes obtuse, adaxial faces villous.
1–50, borne singly or in open corymbiform arrays.
5–30+ in flat-topped, corymbiform arrays.
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.
tawny, fusiform, 3–3.5 mm, slightly compressed, ribs 7–9 (brown, translucent), faces strigillose;
pappi of tawny bristles 2.7–3 mm, ± equaling disc corollas.
= 18.
= 18, 27.
Eurybia sibirica
Eurybia radulina
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 radulina is confined mostly west of the Cascades, from southern Vancouver Island (British Columbia) to the southern Coast Ranges, north Channel Islands, and central Sierra Nevada in California. It often is confused with E. merita in the western, coastal states where both are found, though populations are rarely if ever sympatric, the former apparently thriving at lower elevations than the latter.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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