Symphyotrichum retroflexum |
Symphyotrichum chapmanii |
|
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rigid whitetop aster |
savanna aster |
|
Habit | Perennials, 40–100 cm, usually colonial, sometimes ± cespitose; short-(seldom long-)rhizomatous. | Perennials, 30–80 cm, cespitose; rhizomes stout. |
Stems | 1–2+, erect (straight to slightly flexuous, sometimes robust), glabrous. |
1–3+, erect (sometimes brown proximally, strict to straight), glabrous. |
Leaves | thin to firm, margins slightly recurved, scabrous, faces glabrous; basal mostly withering by flowering, petiolate (petioles narrowly winged, sheathing), blades lanceolate-ovate to ovate or spatulate, 25–110 × 10–40 mm, bases usually rounded to attenuate, seldom ± cordate, margins serrulate to shallowly serrate, apices obtuse to acute; proximal cauline often withering by flowering, petiolate (petioles ± widely winged, ± clasping), blades lance-ovate or narrowly ovate, 50–95 × 19–31 mm, bases usually rounded to attenuate, sometimes cuneate, rarely subcordate, margins serrate to serrulate; distal winged-petiolate or subpetiolate or sessile, blades lance-ovate or narrowly ovate to lanceolate or sometimes linear (in arrays), 7–1.5 × 3–31 mm, gradually and strongly reduced distally, bases cuneate, scarcely or not clasping, to slightly rounded and ± clasping, margins serrulate or entire, apices acute to acuminate. |
green to dark green, firm, ± fleshy, margins entire, ciliate, apices acute, callous, faces sparsely strigillose; basal persistent or petiole bases marcescent, long-petiolate (to 15 cm; petioles sheathing, margins glabrous), blades linear to linear-lanceolate, 10–30 × 2–7 mm, bases cuneate to subattenuate, margins sparsely denticulate or entire, indurate-translucent; proximal cauline persistent, sessile or subpetiolate, blades linear, 42–105 × 1–3 mm, bases clasping, margins often revolute; distal sessile, blades usually linear, sometimes awl-shaped, 50–180 × 5–10 mm, strongly reduced distally, more abruptly so on array branches, bases subclasping to adnate for 1/2+ length, margins often revolute. |
Peduncles | (when present) 0.2–1.5 cm, densely pilose or pilosulous, bracts 1–6+, lanceolate to oblong-lanceolate, foliaceous to distally grading into phyllaries. |
1–20+ cm, slender, glabrous, bracts 4–22, linear (awl-shaped), grading into phyllaries. |
Involucres | campanulate, (6–)7–10 mm. |
cylindro-campanulate, 5.5–9 mm. |
Ray florets | 13–30; corollas blue to purple, laminae (10–)15–17 × 1.6–3 mm. |
8–23; corollas purple to blue-lavender, laminae (10–)14–15(–20) × 0.8–2.2 mm. |
Disc florets | 35–50+; corollas cream to pale yellow becoming pinkish, 5.8–6.8 mm, tubes shorter than funnelform throats, lobes lanceolate, 0.9–1.2 mm, glabrous. |
47–57; corollas pale yellow, 4.7–6.3 mm, throats funnelform to narrowly campanulate, lobes triangular, 0.5–0.7 mm (proximally sparsely pilose). |
Phyllaries | in 3–4(–5) series, broadly lanceolate constricted to narrow oblong bases (outer) to oblong-lanceolate or linear-lanceolate (inner), ± unequal, bases indurate 1/10–1/5 (outer) to 4/5+ (inner), margins hyaline, narrowly scarious, erose (indurate portion), sparsely ciliolate (foliaceous portion), green zones foliaceous (outer) to distal 1/5–1/4 foliaceous (inner), basally truncate to lanceolate, apices spreading to squarrose, acute to acuminate, mucronulate, abaxial faces glabrous or glabrate, adaxial strigillose (foliaceous portion). |
in 4–5(–6) series, oblong-lanceolate (outer) to linear-lanceolate (innermost), bases indurate (at least inner), margins scarious, hyaline, purplish distally, ciliolate, green zones narrowly lanceolate, not evident, apices purplish, acute (outer) to acuminate (inner), sometimes mucronate (inner), faces sparsely villous. |
Heads | in broad (appearing ± corymbiform) or narrow, paniculiform to ± racemiform arrays, branches usually long (to 10 cm), ascending to divaricate. |
in open, usually corymbiform, sometimes ± paniculiform arrays, branches ascending, simple, slender, elongate. |
Cypselae | tan, obovoid to oblanceoloid, compressed, 3–3.9 mm, 4–6-nerved, faces glabrous or sparsely strigillose; pappi whitish to reddish, 5.3–6 mm. |
tan to gray-brown (nerves stramineous), obovoid, compressed, 3.1–4.5 mm, 8–10(–14)-nerved, faces glabrous; pappi yellowish, 4.4–4.7 mm. |
2n | = 48. |
= 14. |
Symphyotrichum retroflexum |
Symphyotrichum chapmanii |
|
Phenology | Flowering Aug–Oct. | Flowering Sep–Nov(–Dec). |
Habitat | Moist meadows, moist woodlands, dry, open, pine or oak woods, wooded roadsides | Wet savannas, pine flatwoods, bogs, and acid swamps |
Elevation | 400–1500 m (1300–4900 ft) | 0–30 m (0–100 ft) |
Distribution |
AL; GA; NC; SC; TN; VA
|
AL; FL |
Discussion | Symphyotrichum retroflexum is known only from the Appalachian Blue Ridges. It is possible that the species is an allopolyploid derived from members of subsections Cordifolii and Symphyotrichum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Symphyotrichum chapmanii is known from the Appalachicola Valley, northern Florida and adjacent southeast Alabama (where it is possibly extirpated), and is disjunct to St. Lucie County (Florida). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 510. | FNA vol. 20, p. 478. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Aster retroflexus, Aster curtisii | Aster chapmanii, Eurybia chapmanii, Heleastrum chapmanii |
Name authority | (Lindley ex de Candolle) G. L. Nesom: Phytologia 77: 291. (1995) | (Torrey & A. Gray) Semple & Brouillet: in J. C. Semple et al., Cult. Native Asters Ontario, 133. (2002) |
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