Symphyotrichum pilosum |
Symphyotrichum yukonense |
|||||
---|---|---|---|---|---|---|
aster poilu, awl American-aster, frost aster, hairy aster, hairy white Oldfield aster, Oldfield or frost weed or white Oldfield or hairy or hairy white Oldfield aster, white heath aster |
Yukon aster |
|||||
Habit | Perennials cespitose, (5–)20–120(–150+) cm; with stout, branched caudices, sometimes long-rhizomatous. | Perennials cespitose or colonial, 5–30 cm; with short, erect, woody caudices from long, thin rhizomes. | ||||
Stems | 1–5+, ascending to erect (straight, stout), glabrate to hirsuto-hispid or pilose, sometimes glabrous or hairy in lines (var. pringlei). |
1–8+, erect (purplish to brown, slender), villous, more densely so distally, distally moderately stipitate-glandular. |
||||
Leaves | thin, margins ciliate, apices acute to acuminate, mucronate, faces glabrous or ± hirsute (particularly on abaxial midveins); basal withering by flowering (new vernal rosettes developing at flowering), petiolate to subpetiolate (petioles winged, ciliate, bases sheathing), blades oblanceolate or obovate to spatulate, 10–60 × 5–15 mm, bases attenuate, margins sparsely crenate-serrate (mostly apically), apices obtuse to rounded; proximal cauline usually deciduous at flowering (often with axillary clusters of small leaves), petiolate or subpetiolate to subsessile (petioles narrowly to broadly winged, clasping), blades elliptic-oblanceolate or -oblong to linear-lanceolate or -oblanceolate, 40–102 × 5–25 mm, progressively reduced distally, bases attenuate to cuneate, ± clasping, margins entire to serrate, softly ciliate, apices attenuate, hyaline-spinulose; distal sessile, blades lance-oblong to linear-lanceolate to linear or linear-oblanceolate or linear-subulate, 10–100 × 1–8 mm, progressively reduced distally, branch leaves abruptly smaller, bases cuneate, margins entire or serrulate. |
(yellowish to dark green. |
||||
Peduncles | 5–30(–50) mm, progressively shorter distally, glabrous or densely hispid, bracts 7–25+, appressed to ascending, sometimes ± spreading, linear to subulate, glabrate, ciliate or not, mucronate to apiculate, ± grading into phyllaries. |
± densely short-villous, ± densely stipitate-glandular, bracts 1–3, foliaceous, reduced. |
||||
Involucres | campanulate to cylindro-campanulate, (2.5–)3.5–5.1(–6.5) mm. |
campanulate, 7–10 mm. |
||||
Ray florets | (10–)16–28(–38); corollas usually white, rarely pinkish or bluish, laminae (4–)5.4–7.5(–11) × (0.4–)0.8–1.3(–1.7) mm. |
(8–)15–30; corollas purple to blue, laminae 5–11 × 0.5–2 mm. |
||||
Disc florets | (13–)17–39(–67); corollas light yellow becoming reddish purple or brown, (2.5–)3–4.1(–5.5) mm, tubes much shorter than narrowly funnelform throats, lobes lanceolate, (0.4–)0.6–0.8(–1) mm. |
16–38; corollas yellow becoming brown, 4–6.5 mm, lobes triangular, 0.4–0.8 mm. |
||||
Phyllaries | in 4–6 series, appressed or slightly spreading, oblong-lanceolate (outer) to linear (innermost) , unequal (rarely subequal), bases indurate 1/2–3/5, margins hyaline, scarious, erose, ± ciliolate distally, green zones lanceolate to lance-rhombic, apices acute or acuminate, involute, spinulose, faces glabrous or sparsely hirsutulous. |
in 3–4(–5) series, linear-lanceolate, subequal, bases scarious, margins hyaline or purplish, scarious, erose, ciliate or short-stipitate-glandular, green zones herbaceous at least distally, often purplish to purple, apices long-acuminate, spreading to reflexed, faces ± densely villous (outer more so), ± densely stipitate-glandular. |
||||
Heads | in open, leafy, often pyramidal, paniculiform arrays, branches divaricate or branches 10 cm or less ascending, often arched and secund, sometimes racemiform. |
usually borne singly, sometimes in open, corymbo-paniculiform arrays, branches ascending. |
||||
Cypselae | whitish or gray, oblong-obovoid, sometimes ± compressed, 1–1.5 × 0.5–0.7 mm, 4–6-nerved, faces sparsely strigillose; pappi white, 3.5–4 mm. |
brown (sometimes purplish, nerves stramineous), narrowly obovoid, ± compressed, ca. 3 mm, 7–10-nerved, faces sparsely to moderately sericeo-strigose; pappi sordid (barb tips sometimes purplish-tinged), 3.5–4.8 mm. |
||||
Midrib | purplish, often prominent) thin, reduced distally, margins entire; basal withering by flowering, winged-petiolate to subpetiolate (petioles ± sheathing), blades narrowly oblanceolate, 8–15 × 1–3 mm, bases attenuate, margins scabrous, apices obtuse to acute, faces glabrous or glabrate; proximal cauline often withering by flowering, sessile or subsessile, blades linear-oblanceolate, 20–70 × 1–4 mm, bases ± clasping, margins ciliate, apices acute, abaxial faces glabrous or midnerve ± sparsely villous, adaxial glabrous or sparsely villous, midnerves ± villous; distal sessile, blades linear-lanceolate, 10–30 × 1–2.5 mm, bases ± subclasping, ± rounded to subauriculate, margins sometimes stipitate-glandular, apices acute, mucronate or white-spinulose, faces glabrous or sparsely villous, short-stipitate-glandular. |
|||||
2n | = 10. |
|||||
Symphyotrichum pilosum |
Symphyotrichum yukonense |
|||||
Phenology | Flowering Jul–Aug. | |||||
Habitat | Mud flats, gravelly, stony or silty lakeshores, sometimes saline areas | |||||
Elevation | 300–1500 m (1000–4900 ft) | |||||
Distribution |
AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; VA; VT; WI; WV; BC; NB; NS; ON; QC
|
AK; NT; YT |
||||
Discussion | Varieties 2 (2 in the flora). The ecology and cytogeography of Symphyotrichum pilosum were summarized by J. G. Chmielewski and J. C. Semple (2001b). The species is often confused with S. ericoides, which inhabits the same kinds of open, prairie-like habitats; the latter can be distinguished by its smaller heads and spine-tipped phyllary apices. Because of that, the name Aster ericoides has been misapplied often in floras and in the horticultural trade. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Symphyotrichum yukonense is distributed disjunctly on the John River in the southern Brooks Range (Alaska), Lake Kluane (Yukon), and the Mackenzie Mountains and middle Mackenzie River (Northwest Territories). It appears closely related to S. pygmaeum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||
Key |
|
|||||
Source | FNA vol. 20, p. 511. | FNA vol. 20, p. 485. | ||||
Parent taxa | Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum | Asteraceae > tribe Astereae > Symphyotrichum > subg. Virgulus | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Aster pilosus, Aster ericoides var. pilosus | Aster yukonensis, Virgulus yukonensis | ||||
Name authority | (Willdenow) G. L. Nesom: Phytologia 77: 289. (1995) | (Cronquist) G. L. Nesom: Phytologia 77: 294. (1995) | ||||
Web links |
|