The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

amethyst aster, aster, hybrid aster

Habit Perennials, 40–100 cm, cespitose, eglandular; with cormoid, woody caudices. Perennials, cespitose, 30–120 cm; with thick, woody, short-branched caudices at ends of fleshy rhizomes.
Stems

5–10+, erect or arching (light to dark brown), proximally sparsely to moderately finely woolly-pilose (hairs spreading to ascending), more densely so distally.

1–5+, erect (light brown to grayish brown), densely hispidulo-hirsute.

Leaves

(grayish) soft;

basal withering by flowering, sessile, blades (1–3-nerved) elliptic-lanceolate, 20–40 × 10–20 mm, bases attenuate, margins usually entire, rarely remotely serrate, piloso-ciliate, apices acute to obtuse, faces silvery piloso-silky;

proximal cauline withering by flowering, sessile, blades oblanceolate, 20–30 × 4–8 mm, bases rounded, subclasping, margins entire, scabrous to silky-piloso-ciliate, apices acute to obtuse, cuspidate-mucronate, faces moderately strigillose;

distal sessile, blades lanceolate to narrowly ovate, 8–15 × 2.5–5 mm, reduced distally, bases cuneate, margins entire, apices acute, mucronate, faces moderately, finely lanoso-strigose.

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

densely hairy, bracts linear, grading into phyllaries.

hispid, bracts 1–3+, oblong-lanceolate, 3–5 mm, not grading into phyllaries.

Involucres

campanulate, 7–9 mm.

campanulate to hemispheric, 4–6 mm.

Ray florets

7–12;

corollas rose-purple, laminae 6–9 × 1–2 mm.

20–35;

corollas azure blue to violet or lavender, laminae 5–10 × 0.6–1.2 mm.

Disc florets

14–20;

corollas pink turning purple, 5–6 mm, tubes shorter than narrowly funnelform throats (thinly puberulent), lobes triangular, 0.3–0.5 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 3–4 series, spreading to reflexed, linear, unequal, bases (tan) ± indurate, margins scarious proximally, green distally, green zones foliaceous, apices acute, faces moderately woolly-strigose.

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

radiate, in narrow, paniculiform (wand-shaped) to sometimes compact, racemiform arrays (1(–3) per branch).

in ample, leafy, paniculiform arrays, branches ascending, sometimes secund (heads often crowded).

Cypselae

fusiform-obovoid, not compressed, 2–3 mm, 6–8-nerved, faces densely strigose;

pappi tan to yellowish tan, (5.5–)6.5–8 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

= 8.

= 10.

Symphyotrichum plumosum

Symphyotrichum ×amethystinum

Phenology Flowering Oct–Nov. Flowering Aug–Oct.
Habitat Deep, dry to moist, sandy soils, pine flatwoods, pine-scrub oak woods, favored by fires and clearcuts Fields, prairies, disturbed grounds
Elevation 0–40 m (0–100 ft) 200–400 m (700–1300 ft)
Distribution
from FNA
FL
[BONAP county map]
from FNA
CO; CT; IA; IL; IN; KY; MA; MD; MN; MO; ND; NE; NJ; NY; PA; RI; VT; WA; WI; ON
[BONAP county map]
Discussion

Symphyotrichum plumosum is known only from Franklin County. It differs from S. concolor var. concolor in its long-acuminate, recurved to reflexed phyllaries. No intermediates with S. concolor were seen in the field.

(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. 493. FNA vol. 20, p. 497.
Parent taxa Asteraceae > tribe Astereae > Symphyotrichum > subg. Virgulus Asteraceae > tribe Astereae > Symphyotrichum > subg. Virgulus
Sibling taxa
S. adnatum, S. anomalum, S. anticostense, S. ascendens, S. boreale, S. bracteolatum, S. campestre, S. chapmanii, S. chilense, S. ciliatum, S. ciliolatum, S. concolor, S. cordifolium, S. cusickii, S. defoliatum, S. depauperatum, S. drummondii, S. dumosum, S. elliottii, S. ericoides, S. eulae, S. falcatum, S. fendleri, S. firmum, S. foliaceum, S. fontinale, S. frondosum, S. georgianum, S. grandiflorum, S. greatae, S. hallii, S. hendersonii, S. jessicae, S. laeve, S. lanceolatum, S. lateriflorum, S. laurentianum, S. lentum, S. molle, S. nahanniense, S. novae-angliae, S. novi-belgii, S. oblongifolium, S. ontarionis, S. oolentangiense, S. parviceps, S. patens, S. phlogifolium, S. pilosum, S. porteri, S. potosinum, S. praealtum, S. pratense, S. prenanthoides, S. priceae, S. puniceum, S. pygmaeum, S. racemosum, S. retroflexum, S. rhiannon, S. robynsianum, S. sericeum, S. shortii, S. simmondsii, S. spathulatum, S. subspicatum, S. subulatum, S. tenuifolium, S. tradescantii, S. turbinellum, S. undulatum, S. urophyllum, S. walteri, S. welshii, S. yukonense, S. ×amethystinum
S. adnatum, S. anomalum, S. anticostense, S. ascendens, S. boreale, S. bracteolatum, S. campestre, S. chapmanii, S. chilense, S. ciliatum, S. ciliolatum, S. concolor, S. cordifolium, S. cusickii, S. defoliatum, S. depauperatum, S. drummondii, S. dumosum, S. elliottii, S. ericoides, S. eulae, S. falcatum, S. fendleri, S. firmum, S. foliaceum, S. fontinale, S. frondosum, S. georgianum, S. grandiflorum, S. greatae, S. hallii, S. hendersonii, S. jessicae, S. laeve, S. lanceolatum, S. lateriflorum, S. laurentianum, S. lentum, S. molle, S. nahanniense, S. novae-angliae, S. novi-belgii, S. oblongifolium, S. ontarionis, S. oolentangiense, S. parviceps, S. patens, S. phlogifolium, S. pilosum, S. plumosum, S. porteri, S. potosinum, S. praealtum, S. pratense, S. prenanthoides, S. priceae, S. puniceum, S. pygmaeum, S. racemosum, S. retroflexum, S. rhiannon, S. robynsianum, S. sericeum, S. shortii, S. simmondsii, S. spathulatum, S. subspicatum, S. subulatum, S. tenuifolium, S. tradescantii, S. turbinellum, S. undulatum, S. urophyllum, S. walteri, S. welshii, S. yukonense
Synonyms Aster plumosus, S. concolor var. plumosum Aster amethystinus, Virgulus ×amethystinus
Name authority (Small) Semple: in J. C. Semple et al., Cult. Native Asters Ontario, 134. (2002) (Nuttall) G. L. Nesom: Phytologia 77: 294. (1995)
Web links