Symphyotrichum anticostense |
Symphyotrichum ×amethystinum |
|
---|---|---|
Anticosti American-aster, Anticosti aster, Anticosti Island aster, aster d'Anticosti |
amethyst aster, aster, hybrid aster |
|
Habit | Perennials, 10–90 cm, colonial; long-rhizomatous. | Perennials, cespitose, 30–120 cm; with thick, woody, short-branched caudices at ends of fleshy rhizomes. |
Stems | 1, erect (straight, often reddish), glabrous. |
1–5+, erect (light brown to grayish brown), densely hispidulo-hirsute. |
Leaves | coriaceous, margins remotely serrulate or entire, slightly revolute, scabrous, apices mucronulate, faces glabrous; basal withering by flowering, long-petiolate (petioles narrowly winged, bases sheathing), blades lanceolate to oblanceolate, ca. 55+ × 3+ mm, bases slightly attenuate, apices acute; proximal cauline mostly withering by flowering, petiolate (petioles narrowly winged, sheathing), blades lanceolate or oblanceolate to linear-lanceolate or -oblanceolate, arcuate, 90–160 × 5–18 mm, bases cuneate to slightly attenuate, margins entire or serrulate, apices acute; distal sessile, blades linear to linear-lanceolate, 8–50 × 1.5–5 mm, progressively reduced distally, more strongly so in arrays, bases cuneate to rounded, sometimes slightly clasping, apices acute to acuminate. |
light green, thin to firm; basal withering by flowering, sessile, blades oblanceolate, 10–40 × 3–10 mm, attenuate, margins usually entire, rarely remotely serrate, piloso-ciliate, apices obtuse, rounded to mucronulate, faces sparsely to moderately strigose; proximal cauline sometimes persistent by flowering, sessile, blades linear or oblong to elliptic-oblanceolate, 40–60 × 3–10 mm, bases rounded or slightly clasping, margins entire, scabrous, apices acute to obtuse, faces ± copiously hirsute; distal sessile, blades oblanceolate, 15–45 × 2–3(–4.5) mm, progressively reduced distally, bases cuneate, margins entire, apices acute, white-spine-tipped, faces sparsely strigose. |
Peduncles | 0.8–5.7 cm, slender, sparsely ot moderately pilosulous, bracts 3–5, linear-lanceolate, often crowded proximal to and surpassing heads. |
hispid, bracts 1–3+, oblong-lanceolate, 3–5 mm, not grading into phyllaries. |
Involucres | campanulate, 6–10 mm. |
campanulate to hemispheric, 4–6 mm. |
Ray florets | 25–44; corollas usually pale purple or lilac, sometimes white, laminae 9.5–20 × 0.7–1.4 mm. |
20–35; corollas azure blue to violet or lavender, laminae 5–10 × 0.6–1.2 mm. |
Disc florets | 29–52; corollas yellow becoming reddish purple, 5–6 mm, tubes slightly shorter than funnelform throats, lobes lanceolate, 0.6–0.7 mm. |
20–30+; corollas light yellow turning pinkish to purple, 3–4 mm, tubes ca. 1/2 narrowly funnelform throats, lobes triangular, 0.5–0.7 mm, glabrous. |
Phyllaries | in 2–3 series, oblong-oblanceolate or -spatulate (outer) or oblong-lanceolate to linear-lanceolate or linear (inner), ± unequal, bases indurate 1/3–3/4, margins hyaline, scarious, erose distally, sparsely ciliolate distally, green zones lanceolate, outer often foliaceous distally, apices acute to long-acuminate, ± spreading, faces glabrous. |
in 3–5 series, linear-lanceolate, ± unequal to subequal, bases ± indurate, margins hyaline proximally, outer distally hispido-scabrous, green zones diamond-shaped, restricted to distal 1/2–1/4, apices (outer) spreading to reflexed, acute, subspinulose, (inner) acuminate, purplish, faces (outer) scabroso-puberulent or strigose, eglandular, inner distally stipitate-glandular. |
Heads | in elongate, loosely racemiform arrays, branches ascending, heads single at ends of primary branches or long pedicels. |
in ample, leafy, paniculiform arrays, branches ascending, sometimes secund (heads often crowded). |
Cypselae | reddish tan, obovoid, compressed, 1.5–2.8 mm, 4–5-nerved, faces strigillose; pappi yellowish, 7–8 mm. |
dull purple or brown, obovoid, not compressed, 1.5–2 mm, 7–9-nerved, faces densely sericeous; pappi tan to tawny, sometimes rose to violet-tinged, 3.5–5.5 mm. |
2n | = 80. |
= 10. |
Symphyotrichum anticostense |
Symphyotrichum ×amethystinum |
|
Phenology | Flowering Aug–Sep. | Flowering Aug–Oct. |
Habitat | Calcareous, gravelly shores of rivers, lakeshore limestone pavements | Fields, prairies, disturbed grounds |
Elevation | 0–100 m (0–300 ft) | 200–400 m (700–1300 ft) |
Distribution |
ME; NB; QC
|
CO; CT; IA; IL; IN; KY; MA; MD; MN; MO; ND; NE; NJ; NY; PA; RI; VT; WA; WI; ON |
Discussion | Of conservation concern. Symphyotrichum anticostense is known from disjunct areas: western Lake St. John, southern Anticosti Island, southern streams of the Gaspé Peninsula (Quebec), Restigouche River (Quebec–New Brunswick), and St. John (New Brunswick) and Aroostook (Maine; A. Haines 2000) rivers. It is an allopolyploid derivative of the cross between the calcareous fen species S. boreale and the widespread shore species S. novi-belgii (J. Labrecque and L. Brouillet 1990). It hybridizes with S. novi-belgii. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Symphyotrichum ×amethystinum is the F1 hybrid between S. ericoides and S. novae-angliae, encountered sometimes throughout the area where the two parental species co-occur. It is morphologically intermediate; it has non-spiny, sparsely stipitate-glandular phyllaries and rose-violet rays in mid-sized heads. Forma leucerythros Bemis and forma leucos Bemis have been described within this hybrid and may represent recombinants or normal population color variants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 529. | FNA vol. 20, p. 497. |
Parent taxa | Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum | Asteraceae > tribe Astereae > Symphyotrichum > subg. Virgulus |
Sibling taxa | ||
Synonyms | Aster anticostensis, Aster gaspensis, Aster hesperius var. gaspensis | Aster amethystinus, Virgulus ×amethystinus |
Name authority | (Fernald) G. L. Nesom: Phytologia 77: 275. (1995) | (Nuttall) G. L. Nesom: Phytologia 77: 294. (1995) |
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