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Welsh's aster

alkali aster, leafy annual American-aster, short-ray alkali aster, short-ray aster

Habit Perennials, 30–100 cm colonial; rhizomes shallow and long, often relatively thick (those of the season each producing a distal rosette near the parent plant). Annuals or sometimes perennials, 5–140 cm.
Stems

1–2, ascending to erect (sometimes lax, sometimes reddish), glabrous or sparsely strigoso-villosulous distally (arrays).

1–6+, decumbent to erect (straight), glabrous.

Leaves

(adaxially green, abaxially pale green, sometimes glaucous) thin (proximal) to stiff (distal), margins serrulate (proximal) or entire or nearly so, ± revolute, scabrous, apices mucronulate or sometimes callous-pointed, faces glabrous;

basal withering by flowering, petiolate (petioles narrowly winged, sheathing), blades oblanceolate to spatulate, 10–40+ × 4–9+ mm, bases attenuate, margins entire, apices obtuse;

proximal cauline withering by flowering, sessile or winged-petiolate, blades lanceolate to oblanceolate, 50–150 × 8–11 mm, bases slightly clasping, margins sparsely serrulate, apices acute;

distal sessile, blades linear to linear-lanceolate, 50–130 × 4–6 mm, gradually reduced distally, bases ± clasping, apices acute.

thin, margins entire (basal sometimes serrulate), sometimes ciliate or remotely scabrous, acute to ± obtuse, faces glabrous;

basal withering by flowering, petiolate, blades oblanceolate to spatulate, 20–115 × 2–15 mm [cult.], bases attenuate;

proximal cauline withering by flowering;

cauline subpetiolate or sessile (distal), blades oblanceolate to linear, 10–80 × 1.5–10 mm, reduced distally, bases cuneate.

Peduncles

0.5–2 cm, scabro-villosulous, bracts linear, scabro-ciliolate.

glabrous, bracts linear.

Involucres

cylindro-campanulate, 4–7 mm.

narrowly campanulate, 5–9 mm.

Ray florets

18–25;

corollas pink to white, laminae 9–12 × 0.8–1.5 mm.

90–110 in 4–5+ series;

corollas pink to pinkish white, laminae 1.5–2 × 0.1–0.2 mm (surpassing style branches, barely surpassing disc corollas; tubes ± 3 mm).

Disc florets

23–60;

corollas pale yellow, 3.8–6.4 mm, tubes shorter than funnelform throats, lobes narrowly triangular, 0.4–0.8 mm.

± 37;

corollas yellow, 4.4–5.2 mm, barely ampliate, tubes much longer than cylindric limbs, lobes lanceolate, ± 0.3 mm.

Phyllaries

in 3–4 series, lanceolate (outer) to linear (inner), ± unequal, bases indurate, margins hyaline, erose, distally scabro-ciliolate to ciliolate, green zones ± foliaceous (outer) or lanceolate, apices acute to acuminate, sometimes purplish, faces glabrous.

in 3–4 series, ± spreading, oblong-oblanceolate or -lanceolate to obovate, subequal to ± unequal, linear-lanceolate or linear (innermost), bases scarious, margins narrowly scarious, hyaline, erose, ciliolate, green zones (outer) foliaceous, (inner) lanceolate, apices obtuse to rounded, inner acute, mucronulate, faces glabrous.

Heads

in open, slender, leafy, paniculiform or racemiform arrays, branches ascending.

(radiate) in narrow, paniculiform to spiciform arrays, branches often in axils of nearly every leaf, ascending.

Cypselae

pinkish tan (nerves stramineous), obovoid, ± compressed, 0.8–1.6 mm, 3–5-nerved, faces sparsely strigillose;

pappi white, 2.8–5.3 mm.

tan, obovoid, ± compressed, 2 mm, 2–3-nerved, faces strigillose;

pappi white to yellowish, 6.3–7.5 mm.

2n

= 16.

= 14.

Symphyotrichum welshii

Symphyotrichum frondosum

Phenology Flowering Aug–Oct. Flowering Aug–Oct.
Habitat Wet soils in dry areas, hanging gardens, seeps, wet ledges, stream banks Moist, usually saline soils, summer-receding shores of lakes or ponds, vernally moist, alkaline bottoms, marshes, often in steppes
Elevation 1300–2300 m (4300–7500 ft) 10–2200 m (0–7200 ft)
Distribution
from FNA
AZ; ID; MT; UT; WY
[BONAP county map]
from FNA
AZ; CA; CO; ID; NM; NV; OR; UT; WA; WY; BC; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

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

Source FNA vol. 20, p. 523. FNA vol. 20, p. 499.
Parent taxa Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Conyzopsis
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. subspicatum, S. subulatum, S. tenuifolium, S. tradescantii, S. turbinellum, S. undulatum, S. urophyllum, S. walteri, 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. 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, S. ×amethystinum
Synonyms Aster welshii Tripolium frondosum, Aster frondosus, Brachyactis frondosa
Name authority (Cronquist) G. L. Nesom: Phytologia 77: 294. (1995) (Nuttall) G. L. Nesom: Phytologia 77: 282. (1995)
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