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aster à rameaux étalés, white wood-aster

aster rude, low rough aster, rough wood-aster

Habit Plants 28–90(–120) cm, in ± dense clones (lacking sterile rosettes); rhizomes branched, elongate, becoming woody. Plants 10–100 cm; in lax clones, eglandular; rhizomes elongate or short, filiform or cordlike, herbaceous, remotely scaly.
Stems

1, erect, simple, flexuous, glabrate to sparsely puberulent proximally, densely puberulent distally.

1, erect, straight, often reddish, simple, glabrous or glabrescent to sparsely villous proximally, villous distally.

Leaves

basal and cauline, thin, margins sharply serrate, teeth (6–15 per side) mucronulate, ciliate, apices acuminate, abaxial faces sparsely strigose or villous, particularly villous along veins, adaxial glabrescent to sparsely strigose, veins sparsely stipitate-glandular;

basal and proximal withering by flowering, petiolate (petioles 20–70 mm), blades ovate, 19–65 × 17–60 mm, basal smaller than proximal, bases cordate (sinuses narrow, curved);

cauline petiolate, petioles often ± winged (15–70 mm), blades ovate, 20–200 × 10–100 mm, bases cordate to rounded;

distal (arrays) usually sessile, sometimes subpetiolate, blades ovate to lanceolate, 5–20 × 1–8 mm, bases rounded.

cauline, rugose-veined, margins ± revolute, ± remotely, ± deeply serrate, scabrous, teeth ± indurate (mucronate), apices mucronulate, abaxial faces scabrous, adaxial ± villous, particularly on veins (increasingly so distally);

proximalmost withering by flowering, winged-petiolate, petioles equaling or longer than blades, bases ± sheathing, sometimes marcescent, blades spatulate to oblanceolate, 10–42 × 3–8 mm, sometimes reduced, smaller than mid, bases attenuate to cuneate, apices obtuse to acute;

mid sessile, lanceolate, oblanceolate, or narrowly obovate to narrowly elliptic or elliptic, (23–)30–115 × 5–36 mm, gradually reduced distally, bases tapering or rounded to ± auriculate-clasping (often narrowed above base), apices acute to acuminate;

distal (arrays) sessile, (6–)10–40 × 2–7 mm.

Peduncles

to 1.5 cm, densely hairy, eglandular;

bracts 0(–2).

± densely villous;

bracts 0–2, sometimes subtending heads.

Involucres

cylindro-campanulate, 4.2–6 mm, much shorter than pappi.

campanulate, 5.5–9 mm, shorter than pappi.

Ray florets

5–10(–12);

corollas white, 6–12 × 1.5–2.2 mm.

13–30;

corollas pale blue-violet, 10.5–15 × 1.4–2 mm.

Disc florets

12–19(–25);

corollas yellow, 4.1–4.8(–5.5) mm, abruptly ampliate, tubes (2.3–2.6 mm) longer than campanulate throats (0.9–1.2 mm), lobes reflexed, lanceolate, 0.7–1.4 mm.

37–72;

corollas yellow, 4.5–6 mm, slightly ampliate, 4.8–5.8 mm, tube lengths about twice funnelform throats (2.7–3.4 mm), lobes erect, lanceolate, 0.6–1 mm.

Phyllaries

25–30 in 4–5 series, inner purplish distally, oblong (outer) to lanceolate or linear-lanceolate (inner), strongly unequal, bases indurate, green zones in distal 1/2 (outer) to 1/3 or along distal midveins (inner), margins narrowly scarious, densely fimbriate-ciliate, apices rounded to acute, faces sparsely hairy, sometimes sparsely stipitate-glandular;

outer 0.7–1.5 mm wide, lengths seldom more than 2.5 times widths.

30–50 in 4–5 series, oblong or oblong-lanceolate, seldom ovate (outer), lanceolate to linear-lanceolate (inner), strongly unequal, membranous, bases indurate, rounded (outer), green zones full-width, occasionally purplish (inner), in distal 1/2 (outer; rarely 2/3 and foliaceous) to less than 1/6 and paler or none (inner), margins hyaline (seldom purplish), narrowly scarious, ± erose, densely ciliate, apices usually appressed, often squarrose, usually acute, sometimes obtuse, mucronulate, faces glabrous or sparsely strigillose.

Heads

4–50(–100+) in ± flat-topped corymbiform arrays.

1–25+ in open corymbiform arrays or borne singly.

Cypselae

brown, cylindro-obovoid, slightly compressed, 2.6–3.8 mm, ribs 7–10 (tan to stramineous), faces sparsely strigillose;

pappi of reddish to cream-colored (fine, barbellulate, sometimes apically ± clavate) bristles 3.7–5 mm, equaling or longer than disc corollas.

tawny to stramineous, fusiform to cylindro-obconic, slightly compressed, 2.7–3.5 mm, ribs 8–18 (stramineous or reddish brown), ± crowded, faces glabrous;

pappi of pale cinnamon bristles 4.5–5.2 mm, shorter than disc corollas.

2n

= 18.

= 18.

Eurybia divaricata

Eurybia radula

Phenology Flowering late summer–fall. Flowering late summer–early fall.
Habitat Dry to mesic, eastern deciduous and mixed deciduous woods, edges and clearings, roadsides Fens, sphagnum bogs, lake and creek shores, edges of or openings in wet spruce or tamarack forests, open boggy woods, ± wet meadows, ditches
Elevation 0–1200(–1700) m (0–3900(–5600) ft) 0–600+ m (0–2000+ ft)
Distribution
from FNA
AL; CT; DC; DE; GA; KY; MA; MD; ME; MI; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WV; ON; QC [Introduced in Europe (Netherlands)]
[WildflowerSearch map]
[BONAP county map]
from FNA
CT; DC; DE; KY; MA; MD; ME; NH; NJ; NY; PA; RI; VA; VT; WV; NB; NL; NS; ON; PE; QC; SPM
[WildflowerSearch map]
[BONAP county map]
Discussion

Eurybia divaricata is a mainly Appalachian element of the eastern North American deciduous forest. It is often confused with Eurybia chlorolepis (see W. F. Lamboy 1992 for distinction between the two species), E. schreberi, or Symphyotrichum cordifolium. Lamboy provided a map of the species.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Eurybia radula reaches its northwestern limit south of James Bay in northeastern Ontario, where it is rare (J. C. Semple et al. 2002). It is vulnerable in most of its United States range. Aster radula var. strictus (Pursh) A. Gray (for which no combination exists in Eurybia) appears to be a reduced, more slender plant with 1–8 heads (M. L. Fernald 1950) from more northern parts of the range (Newfoundland and Labrador, northern Quebec, northern Nova Scotia), presumably due to harsher conditions; an entire spectrum of intermediates appears to exist with the typical variety to the south, however, and it is unclear whether the variety should be recognized. It seems that the common name, rough aster, stems from a misinterpretation of the Latin epithet radula, which means scraper (rough would be radulans).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 20, p. 374. FNA vol. 20, p. 371.
Parent taxa Asteraceae > tribe Astereae > Eurybia Asteraceae > tribe Astereae > Eurybia
Sibling taxa
E. avita, E. chlorolepis, E. compacta, E. conspicua, E. eryngiifolia, E. furcata, E. hemispherica, E. integrifolia, E. jonesiae, E. macrophylla, E. merita, E. mirabilis, E. paludosa, E. radula, E. radulina, E. saxicastelli, E. schreberi, E. sibirica, E. spectabilis, E. spinulosa, E. surculosa, E. ×herveyi
E. avita, E. chlorolepis, E. compacta, E. conspicua, E. divaricata, E. eryngiifolia, E. furcata, E. hemispherica, E. integrifolia, E. jonesiae, E. macrophylla, E. merita, E. mirabilis, E. paludosa, E. radulina, E. saxicastelli, E. schreberi, E. sibirica, E. spectabilis, E. spinulosa, E. surculosa, E. ×herveyi
Synonyms Aster divaricatus, Aster boykinii, Aster castaneus, Aster corymbosus, Aster corymbosus var. alatus, Aster excavatus, Aster flexilis, Aster stilettiformis, Aster tenebrosus, Biotia corymbosa, Biotia corymbosa var. alata, Biotia macrophylla var. divaricata, E. corymbosa Aster radula, Aster radula var. strictus
Name authority (Linnaeus) G. L. Nesom: Phytologia 77: 259. (1995) (Aiton) G. L. Nesom: Phytologia 77: 261. (1995)
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