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

Santa Rita Mountain aster

aster à longues feuilles, longleaf aster, Robyns' aster

Habit Perennials, 15–35(–45) cm, colonial or cespitose; rhizoma-tous. Perennials, 10–80 cm, colonial; long-rhizomatous.
Stems

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

1, erect (± flexuous, often reddish), glabrous, hairy in lines distally.

Leaves

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.

stiff, margins sparsely serrulate or entire, ± revolute, scabrous, apices acute to acuminate, mucronulate, faces glabrous, sometimes midveins hairy;

basal withering by flowering, long-petiolate, petioles narrowly winged, bases sheathing, blades lanceolate, ca. 20 × 3–5 mm, slightly attenuate to narrowly cuneate;

proximal cauline withering by flowering, sessile or subpetiolate, blades linear-lanceolate to -oblanceolate, 100–200 × 4–8 mm, bases cuneate to attenuate, clasping;

distal sessile, blades linear-lanceolate to linear, 10–110 × 1–7 mm, progressively reduced distally, bases cuneate to rounded, slightly clasping or not, margins entire.

Peduncles

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

glabrous or ± densely pilose in lines, bracts 1–4, linear, sometimes inrolled distally, clasping, ciliate, distal 1–2 often subtending and surpassing involucres.

Involucres

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

campanulate, 5–8.5 mm.

Ray florets

14–27;

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

20–35;

corollas dark blue-violet, seldom white, laminae 8–13 × 1–1.5 mm.

Disc florets

18–35(–42);

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

(18–)23–40;

corollas yellow, 4–6.5 mm, tubes shorter than funnelform throats, lobes lanceolate, 0.8–1 mm.

Phyllaries

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].

in 3–4 series, oblong-lanceolate, subequal, bases indurate 1/3–3/4, margins scarious, erose, hyaline, ciliate proximally, sparsely ciliolate distally, green zones lanceolate to linear, sometimes outer ± foliaceous, apices acuminate to long-acuminate, often foliaceous, mucronate to apiculate, faces glabrous, eglandular.

Heads

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

in elongate, open, narrow, paniculiform or racemiform arrays, branches ascending, short, leafy, branch leaves smaller and reduced distally (heads 1–3 per branch).

Cypselae

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.

tan, obovoid, compressed, ca. 2.2–2.4 mm, 5–6-nerved, faces sparsely strigillose;

pappi pinkish, 7–8 mm.

2n

= 10.

= 64, 80.

Symphyotrichum potosinum

Symphyotrichum robynsianum

Phenology Flowering (Jun–)Jul–Sep. Flowering Aug–Sep.
Habitat Moist, muddy, sandy, or rocky soils along streams Wet or damp, open, sandy, gravelly, or rocky grounds, often calcareous, cracks in rocky stream or lake shores, limestone alvars, seasonally wet glades and swales, jackpine outwash plains
Elevation 1500–1900 m (4900–6200 ft) 10–400 m (0–1300 ft)
Distribution
from FNA
AZ; Mexico
[BONAP county map]
from FNA
MI; MN; WI; MB; ON; QC
[WildflowerSearch map]
[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.)

The name Aster longifolius Lamarck has been misapplied to this taxon.

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

Source FNA vol. 20, p. 480. FNA vol. 20, p. 530.
Parent taxa Asteraceae > tribe Astereae > Symphyotrichum > subg. Astropolium 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. 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. 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 potosinus, Aster lemmonii Aster robynsianus
Name authority (A. Gray) G. L. Nesom: Phytologia 77: 289. (1995) (J. Rousseau) Brouillet & Labrecque: Phytologia 82: 138. (1997)
Web links