Symphyotrichum retroflexum

(Lindley ex de Candolle) G. L. Nesom

Phytologia 77: 291. 1995.

Common names: Rigid whitetop aster
Endemic
Basionym: Aster retroflexus Lindley ex de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 244. 1836
Synonyms: Aster curtisii Torrey & A. Gray
Treatment appears in FNA Volume 20. Treatment on page 510. Mentioned on page 473, 475, 500.

Perennials, 40–100 cm, usually colonial, sometimes ± cespitose; short- (seldom long-) rhizomatous. Stems 1–2+, erect (straight to slightly flexuous, sometimes robust), 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 lanceovate 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 lanceovate 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. Heads in broad (appearing ± corymbiform) or narrow, paniculiform to ± racemiform arrays, branches usually long (to 10 cm), ascending to divaricate. 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. Involucres campanulate, (6–) 7–10 mm. 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). Ray-florets 13–30; corollas blue to purple, laminae (10–) 15–17 × 1.6–3 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. 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. 2n = 48.


Phenology: Flowering Aug–Oct.
Habitat: Moist meadows, moist woodlands, dry, open, pine or oak woods, wooded roadsides
Elevation: 400–1500 m

Distribution

V20-1138-distribution-map.gif

Ala., Ga., N.C., S.C., Tenn., Va.

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.

Selected References

None.

Lower Taxa

None.

"thin" is not a number.

glabrate +  and glabrous +
not tailed +, rounded +  and obtuse +
distinct +
2.5 cm25 mm <br />0.025 m <br /> (11 cm110 mm <br />0.11 m <br />) +
spreading +  and squarrose +
serrulate to shallowly +
subequal +
scarious +
10mm +  and 40mm +
usually triangular +  and linear +
usually deltate +  and lanceolate +
paniculiform +  and more or less racemiform +
indeterminate +  and determinate +
narrow +  and broad +
Luc Brouillet +, John C. Semple +, Geraldine A. Allen +, Kenton L. Chambers +  and Scott D. Sundberg† +
(Lindley ex de Candolle) G. L. Nesom +
serrate +  and serrulate +
5 cm50 mm <br />0.05 m <br /> (9.5 cm95 mm <br />0.095 m <br />) +
1/10;1/5-4/5 +
linear-lanceolate +, oblong-lanceolate +, oblong +, lanceolate +, rounded +, cuneate +, subcordate +, usually rounded +  and attenuate +
serrulate to shallowly +
unequal +  and constricted to narrow +
indurate +
19mm;31mm +
Aster retroflexus +
0.7 cm7 mm <br />0.007 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
narrowly ovate;lanceolate +
serrulate to shallowly +
reduced +
3mm;31mm +
rugulose +  and muricate +
lanceolate +  and oblong-lanceolate +
barbellulate +  and barbellate +
sessile +  and petiolate +
Rigid whitetop aster +
not 2-lipped +  and actinomorphic +
cream +  and pale-yellow becoming pinkish +
at maturity , more or less ampliate , tubes usually shorter +
0.58 cm5.8 mm <br />0.0058 m <br /> (0.68 cm6.8 mm <br />0.0068 m <br />) +
beaked +, 2-ribbed +  and 5-ribbed +
strigillose +  and glabrous +
compressed +, obovoid +  and oblanceoloid +
fertile +  and bisexual +
fertile +  and bisexual +
sessile +, subpetiolate +  and winged-petiolate +
Ala. +, Ga. +, N.C. +, S.C. +, Tenn. +  and Va. +
400–1500 m +
strigillose +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Moist meadows, moist woodlands, dry, open, pine or oak woods, wooded roadsides +
disciform +  and radiate +
indeterminate +
heterogamous +  and homogamous +
each +  and sessile +
0.6 cm6 mm <br />0.006 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (2.2 cm22 mm <br />0.022 m <br />) +
campanulate +
0.7 cm7 mm <br />0.007 m <br /> (1 cm10 mm <br />0.01 m <br />) +
1 cm10 mm <br />0.01 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
15mm;17mm +
2 (?) +  and 5 (?) +
1.6mm;3mm +
sessile +  and petiolate +
cauline +  and basal +
decurrent +
reflexed;spreading;erect +
lanceolate +
entire +, serrulate +  and serrate +
50mm;95mm +
subcordate +, cuneate +, usually rounded +  and attenuate +
serrulate to shallowly +
19mm +  and 31mm +
2-carpellate +
whitish +  and reddish +
persistent +
25 +  and 40 +
0.53 cm5.3 mm <br />0.0053 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
pilosulous +  and pilose +
0.2 cm2 mm <br />0.002 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
Flowering Aug–Oct. +
oblanceolate or spatulate +  and linear +
strongly unequal +  and subequal +
styliferous +, neuter +  and pistillate +
bearing subulate enations +, hairy +  and bristly +
flat;slightly convex +
exalbuminous +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0.1mm;0.2mm +
branched +  and simple +
1 +  and 2 +
appendaged +  and truncate +
papillate +  and smooth +
Aster curtisii +
Symphyotrichum retroflexum +
Symphyotrichum sect. Symphyotrichum +
species +
funnelform-campanulate +  and cylindric +
ampliate +
cespitose +  and colonial +
40 cm400 mm <br />0.4 m <br /> (100 cm1,000 mm <br />1 m <br />) +
tree +, shrub +  and subshrub +
basally truncate +  and lanceolate +