Symphyotrichum boreale |
Symphyotrichum welshii |
|
---|---|---|
aster boréal, northern bog aster, rush American-aster, rush aster, rush or slender white or northern bog aster, slender white aster |
Welsh's aster |
|
Habit | Perennials (5.5–)13–85 cm, colonial; slender (0.6–2.8 mm diam.), long-rhizomatous (rhizomes of season shallow- or deep-seated, not producing rosettes near parent stems). | 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). |
Stems | 1–3+, erect (straight, slender, often reddish to slightly glaucous proximally), glabrous. |
1–2, ascending to erect (sometimes lax, sometimes reddish), glabrous or sparsely strigoso-villosulous distally (arrays). |
Leaves | stiff, margins entire to sparsely subserrulate, revolute, scabrellous, apices mucronulate, sometimes with callous point, faces glabrous, abaxial midveins sometimes sparsely strigillose; basal withering by flowering, subpetiolate to petiolate, petioles winged, base dilated, sheathing, eciliate, blades linear-oblanceolate to ovate or suborbiculate, 20–150 × 5–60 mm, bases attenuate, margins shallowly serrate or entire, apices obtuse to rounded; proximal cauline withering by flowering, sessile or subpetiolate, petioles widely winged, bases strongly clasping, blades linear-lanceolate to linear, 15–90 × 2–12 mm, bases attenuate to cuneate or subauriculate, ± clasping, apices obtuse to acute; distal sessile, blades linear-lanceolate (sometimes lanceolate) to linear, (40–)60–150 × 2–6(–8) mm, ± reduced distally, bases subauriculate, subclasping, margins entire or sometimes remotely serrulate, apices acute. |
(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. |
Peduncles | 0.5–5 cm, glabrous, bracts 1–3, remote, linear-lanceolate to linear, reduced distally, not grading into phyllaries (sometimes subtending heads). |
0.5–2 cm, scabro-villosulous, bracts linear, scabro-ciliolate. |
Involucres | cylindro-campanulate, (4–)5–8 mm. |
cylindro-campanulate, 4–7 mm. |
Ray florets | (15–)25–35(–41); corollas white to often pale rose, pale purple or lavender, laminae (7–)10–15(–20) × 1.1–1.5 mm. |
18–25; corollas pink to white, laminae 9–12 × 0.8–1.5 mm. |
Disc florets | (15–)25–30(–40); corollas cream or pale yellow becoming pink or brown purple, 3.7–6.6 mm, tubes shorter than funnelform throats, lobes triangular, 0.5–1 mm. |
23–60; corollas pale yellow, 3.8–6.4 mm, tubes shorter than funnelform throats, lobes narrowly triangular, 0.4–0.8 mm. |
Phyllaries | in 4–5 series, usually appressed, rarely outer recurved, lanceolate or oblong-lanceolate (outer) to linear (innermost) ± unequal to sometimes subequal, bases indurate 1/3–1/2 (sometimes not indurate), margins scarious, erose, hyaline or tinged with reddish purple, sparsely ciliolate, green zones lanceolate to linear-lanceolate, apices acute to acuminate, mucronate to apiculate, often purple or reddish purple (particularly inner), faces glabrous. |
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. |
Heads | borne singly or in open, often lax, racemiform or paniculiform arrays, branches ascending, sparsely leafy. |
in open, slender, leafy, paniculiform or racemiform arrays, branches ascending. |
Cypselae | yellowish tan or purple to brownish with purple streaks or grayish tan (nerves stramineous), obovoid, ± compressed, 0.6–2 mm, 3–5-nerved, faces sparsely strigillose; pappi white, 2.7–6.4 mm. |
pinkish tan (nerves stramineous), obovoid, ± compressed, 0.8–1.6 mm, 3–5-nerved, faces sparsely strigillose; pappi white, 2.8–5.3 mm. |
2n | = 16, 32, 48, 64. |
= 16. |
Symphyotrichum boreale |
Symphyotrichum welshii |
|
Phenology | Flowering Aug–Oct. | Flowering Aug–Oct. |
Habitat | Mostly calcareous areas, fens, marshes, bogs, open cedar-tamarack-spruce swamps, stream and pond margins, wet meadows, swales | Wet soils in dry areas, hanging gardens, seeps, wet ledges, stream banks |
Elevation | 0–1500+ m (0–4900+ ft) | 1300–2300 m (4300–7500 ft) |
Distribution |
AK; CO; IA; ID; IL; IN; MA; MI; MN; MT; ND; NE; NH; NJ; NY; OH; PA; SD; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; NT; NU; ON; PE; QC; SK; YT
|
AZ; ID; MT; UT; WY |
Discussion | Some of the western populations originally determined as Symphyotrichum boreale in western Wyoming and adjacent Montana are referable to S. welshii. Those of eastern Wyoming, Colorado, and the Black Hills are S. boreale. There is a gap between the ranges of the two species in Wyoming where neither occurs. Symphyotrichum ×longulum (E. Sheldon) G. L. Nesom (syn. Aster longulus E. Sheldon), reported from Minnesota, is the hybrid between S. boreale and S. puniceum var. puniceum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 522. | FNA vol. 20, p. 523. |
Parent taxa | Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum | Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum |
Sibling taxa | ||
Synonyms | Aster laxifolius var. borealis, Aster borealis, Aster franklinianus, Aster junciformis | Aster welshii |
Name authority | (Torrey & A. Gray) Á. Löve & D. Löve: Taxon 31: 358. (1982) | (Cronquist) G. L. Nesom: Phytologia 77: 294. (1995) |
Web links |