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

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

Santa Rita Mountain aster

Habit Annuals or sometimes perennials, 5–140 cm. Perennials, 15–35(–45) cm, colonial or cespitose; rhizoma-tous.
Stems

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

1–3+, ascending to erect (sometimes purple or purplish brown), glabrous or glabrate, sparsely hairy in leaf axils [villous to sericeous].

Leaves

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.

thin, apices callous-pointed, faces glabrous or glabrate;

basal usually withering by flowering, long-petiolate, petioles sheathing, sparsely ciliate, blades lanceolate, 40–110 × (3–)5–7 mm, bases attenuate, margins entire to crenulate, rarely with 1–2 teeth, apices obtuse to rounded, callus-pointed;

proximalmost cauline sometimes withering by flowering, winged-petiolate or sessile distally, blades lanceolate to linear-lanceolate, 50–120(–180) × 1–6 mm, bases attenuate, margins entire, sparsely ciliate, apices acute;

distal sessile, blades subulate to lanceolate, 10–50 × 1–2 mm, bases clasping, apices acuminate.

Peduncles

glabrous, bracts linear.

1–4(–6) cm, ascending, glabrate, bracts 1–4(–5), subulate to lanceolate, foliaceous.

Involucres

narrowly campanulate, 5–9 mm.

cylindric to hemispheric, (4.5–)5–7.3 mm.

Ray florets

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).

14–27;

corollas white, laminae (4.6–)5.6–7(–9.5)–10.3 × 1.3–2 mm.

Disc florets

± 37;

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

18–35(–42);

corollas yellow, 3.5–5 mm, tubes shorter than funnelform throats (hairy), lobes± spreading, triangular, 0.5–0.7 mm.

Phyllaries

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.

in 2–3(–5) series, subulate to lanceolate, bases indurate, margins hyaline, entire to erose, often ciliate, green zones linear-lanceolate (outer) or rhombic (inner), apices acute, faces glabrous [sparsely villous].

Heads

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

(1–)3–20(–40), in paniculiform arrays, branches patent.

Cypselae

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

pappi white to yellowish, 6.3–7.5 mm.

light brown to gray, narrowly obovoid to fusiform, sometimes ± compressed, 2–3 mm, 5-nerved, faces glabrate to sparsely strigillose;

pappi white to cream, 3.5–5.5 mm.

2n

= 14.

= 10.

Symphyotrichum frondosum

Symphyotrichum potosinum

Phenology Flowering Aug–Oct. Flowering (Jun–)Jul–Sep.
Habitat Moist, usually saline soils, summer-receding shores of lakes or ponds, vernally moist, alkaline bottoms, marshes, often in steppes Moist, muddy, sandy, or rocky soils along streams
Elevation 10–2200 m (0–7200 ft) 1500–1900 m (4900–6200 ft)
Distribution
from FNA
AZ; CA; CO; ID; NM; NV; OR; UT; WA; WY; BC; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; Mexico
[BONAP county map]
Discussion

Of conservation concern.

Symphyotrichum potosinum is known from Cochise County, Arizona, south into Mexico to northern Oaxaca.

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

Source FNA vol. 20, p. 499. FNA vol. 20, p. 480.
Parent taxa Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Conyzopsis Asteraceae > tribe Astereae > Symphyotrichum > subg. Astropolium
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. 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
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. 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 Tripolium frondosum, Aster frondosus, Brachyactis frondosa Aster potosinus, Aster lemmonii
Name authority (Nuttall) G. L. Nesom: Phytologia 77: 282. (1995) (A. Gray) G. L. Nesom: Phytologia 77: 289. (1995)
Web links