Symphyotrichum frondosum |
Symphyotrichum potosinum |
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alkali aster, leafy annual American-aster, short-ray alkali aster, short-ray aster |
Santa Rita Mountain aster |
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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 |
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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 |
AZ; CA; CO; ID; NM; NV; OR; UT; WA; WY; BC; Mexico (Baja California)
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AZ; Mexico |
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.) |
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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 | ||
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) |
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