Symphyotrichum potosinum |
Symphyotrichum robynsianum |
|
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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 |
AZ; Mexico |
MI; MN; WI; MB; ON; QC
|
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 | ||
Sibling taxa | ||
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 |