Symphyotrichum subg. Astropolium

(Nuttall) Semple in J. C. Semple et al.
in J. C. Semple et al., Cult. Native Asters Ontario, 133. 2002.
Basionym: Tripolium subg. Astropolium Nuttall Trans. Amer. Philos. Soc., n. s. 7: 295. 1840
Synonyms: Aster sect. Hesterastrum Bentham Aster sect. Oxytripolium (de Candolle) Torrey & A. Gray Undefined subg. Conyzanthus Tamamschjan Symphyotrichum sect. Oxytripolium (de Candolle) G. L. Nesom Tripolium sect. Oxytripolium de Candolle
Treatment appears in FNA Volume 20. Treatment on page 479. Mentioned on page 461, 466.

Annuals or perennials eglandular; taprooted or rhizomatous. Stems not brittle at maturity, glabrous or glabrate, sometimes sparsely hairy in leaf axils. Leaves: basal withering by flowering, petiolate, blades 1-nerved, spatulate to ovate or obovate, margins entire or shallowly serrate or crenate; cauline subpetiolate or sessile, blades narrowly lanceolate, linear, or subulate, bases attenuate, slightly sheathing, or ± clasping. Heads radiate. Phyllaries unequal (bases indurate), green zones narrowly lanceolate, spatulate to oblanceolate-rhombic, or rhombic (faces glabrous or sparsely hairy). Ray florets 10–30(–54) in 1 series; laminae (1.3–)5–8.5(–9.5) × (0.2–)1.2–2 mm. Disc corollas sometimes weakly ampliate, throats funnelform, lobes ± erect or ± spreading. Cypselae narrowly obovoid to fusiform, sometimes ± compressed, 5–6-nerved, sparsely strigillose or glabrate. x = 5.

Distribution

North America, introduced worldwide.

Discussion

Species ca. 10 (3 in the flora).

Luc Brouillet +, John C. Semple +, Geraldine A. Allen +, Kenton L. Chambers +  and Scott D. Sundberg† +
(Nuttall) Semple in J. C. Semple et al. +
Tripolium subg. Astropolium +
North America +  and introduced worldwide. +
in J. C. Semple et al., Cult. Native Asters Ontario, +
sundberg1986a +
Aster sect. Hesterastrum +, Aster sect. Oxytripolium +, Undefined subg. Conyzanthus +, Symphyotrichum sect. Oxytripolium +  and Tripolium sect. Oxytripolium +
Symphyotrichum subg. Astropolium +
Symphyotrichum +
subgenus +