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Douglas' aster

arrow-leaf American-aster, white arrowleaf aster, white arrowleaf or arrowleaf aster

Habit Perennials, 40–120 cm, colonial; long-rhizomatous. Perennials, 40–120(–200) cm, cespitose; short-rhizomatous or with stout, branched caudices.
Stems

1–5+, ascending to erect, proximally glabrous, distally usually glabrous or sparsely puberulent, rarely densely hirsute.

1–5+, erect (straight to slightly flexuous, brittle, sometimes stout), proximally glabrous or glabrate, distally sparsely pilose.

Leaves

thin, margins entire or often serrate, apices acute, faces glabrous or sparsely puberulent;

basal withering by flowering, petiolate to subpetiolate, blades oblanceolate to narrowly elliptic or linear, 50–150 × 3–25 mm, bases attenuate, margins entire or sometimes serrate, apices acute;

proximalmost cauline withering by flowering, subpetiolate or sessile, blades obovate or oblanceolate to narrowly elliptic, rarely linear, 50–150 × 4–35 mm, bases attenuate or cuneate;

distal sessile, blades 30–100(–130) × 3–15(–30) mm, bases cuneate, rounded or sometimes ± auriculate, margins sometimes serrate, scabrous.

thin, margins usually shallowly, sometimes deeply serrate, rarely entire (distal), (piloso- to strigoso-)ciliate to scabrous (distal), apices mucronate, abaxial faces moderately pilose, ± densely so on midveins, adaxial glabrate to sparsely pilose or scabrous;

basal usually withering by flowering, sometimes persistent, long-petiolate (5–15 cm, petioles not or narrowly winged, sheathing), blades ovate to lance-ovate or lanceolate, 25–120 × 15–50 mm, bases usually shallowly, sometimes deeply, cordate to truncate or rounded, apices acute, sometimes rounded;

proximal cauline sometimes deciduous at flowering, winged-petiolate (petioles distally usually broader-winged, clasping), blades ovate to lanceolate, 50–120 × 20–50 mm, gradually reduced distally, bases usually truncate or rounded to attenuate, sometimes cordate, apices usually acute or acuminate, sometimes nearly caudate;

distal ± shortly winged-petiolate or sessile, blades lance-ovate or lanceolate to linear-lanceolate, 10–100 × 1–25 mm, reduced distally, bases attenuate to cuneate, margins entire to subentire, scabrous, apices acuminate to subcaudate.

Peduncles

sparsely hairy, bracts 1–10, lance-oblong to linear, sometimes clasping, margins scabrous.

0.3–2 cm, sparsely pilosulous to glabrate, bracts many, ascending, linear to subulate, 2–4 mm, grading into phyllaries.

Involucres

campanulate, 5–8(–10) mm.

cylindric, (4–)4.5–6(–7) mm.

Ray florets

15–45;

corollas violet, laminae 10–16(–20) × (1–)1.5–2.5 mm.

8–15(–20);

corollas mostly white to pale pink or lilac or light blue, laminae 4.5–8(–10) × 0.8–1.5 mm.

Disc florets

50–75;

corollas yellow becoming reddish, 4–7 mm, lobes triangular, 0.5–1 mm, glabrous.

(8–)10–15(–20);

corollas whitish to cream becoming pink, (3.5–)4–5 mm, tubes shorter than funnelform throats (with hairs), lobes lanceolate, 0.4–0.7 mm.

Phyllaries

in 4–6 series, appressed or squarrose, oblong or narrowly oblanceolate or linear (outer) to linear (inner), unequal to subequal (outer shorter than or equal to inner, often less than 3 times as long as wide), bases outer indurate less than 1/2 (some foliaceous), inner scarious, margins entire, sometimes ciliate, green zones obovate to elliptic, apices acute to obtuse, faces usually glabrous, rarely sparsely puberulent.

in 4–6 series, appressed or recurved-spreading, subulate (outer) to linear-lanceolate (inner), unequal, bases indurate 1/3–1/2+, margins scarious, hyaline, erose, sparsely ciliolate (mostly distally), green zones linear-lanceolate (outer) to linear (inner), apices long-acuminate to caudate, recurved, hyaline-mucronate to aristate, tips often purple, faces glabrous.

Heads

in open, corymbiform, paniculiform, or racemiform arrays, branches 5–30 cm.

(crowded) in dense, elongate, paniculiform arrays, branches stiffly ascending to erect (sometimes arched when long, peduncles then often secund), usually racemiform, sometimes paniculiform, leafy.

Cypselae

brown or purplish, cylindric to obovoid, not compressed, 2–4 mm, 3–6-nerved, faces hairy;

pappi whitish to tawny or reddish, 4.5–8 mm.

tan to brown or dull purple (nerves stramineous), obovoid, ± compressed, 1.8–2.5 mm, 4–6-nerved, faces glabrous or glabrate or very sparsely strigillose;

pappi white or rose-tinged, 3–4 mm.

2n

= 48, 64, 80, 96.

= 16.

Symphyotrichum subspicatum

Symphyotrichum urophyllum

Phenology Flowering Jul–Sep. Flowering Aug–Oct.
Habitat Marshes, thickets, weedy meadows, open disturbed habitats Open, dry or mesic, sandy or loamy, sometimes rocky soils, limestone pavements, glades, ravines, open oak, sassafras, aspen, or pine woods, edges of woods, moist or dry, rocky bluffs, savanna, wooded banks, stabilized dunes, fields, roadsides, hedgerows, railroads
Elevation 0–1000 m (0–3300 ft) 40–300+ m (100–1000+ ft)
Distribution
from FNA
AK; CA; ID; MT; OR; WA; AB; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; FL; GA; IA; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NJ; NY; OH; OK; PA; SC; TN; VA; VT; WI; WV; ON
[WildflowerSearch map]
[BONAP county map]
Discussion

Symphyotrichum subspicatum is a weedy, highly polyploid species, probably of allopolyploid derivation from different combinations of species including S. chilense, S. bracteolatum, S. foliaceum, S. laeve, and S. spathulatum. Hybrids with S. hallii are known from western Oregon. The species passes into S. foliaceum in southeastern Alaska.

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

The name Aster sagittifolius Wedemeyer ex Willdenow has been misapplied to this taxon; our interpretation of the type of this entity concords with that of A. G. Jones (1980), i.e., that it is conspecific with the type of Symphyotrichum cordifolium or a garden hybrid involving the latter. Aster sagittifolius forma hirtellus (Lindley) Shinners is not recognized here.

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

Source FNA vol. 20, p. 537. FNA vol. 20, p. 506.
Parent taxa Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Occidentales Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum
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. 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. 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. walteri, S. welshii, S. yukonense, S. ×amethystinum
Synonyms Aster subspicatus, Aster butleri, Aster maccallae, Aster subspicatus var. grayi Aster urophyllus, Aster sagittifolius var. dissitiflorus
Name authority (Nees) G. L. Nesom: Phytologia 77: 293. (1995) (Lindley ex de Candolle) G. L. Nesom: Phytologia 77: 294. (1995)
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