Symphyotrichum subg. Astropolium

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).

Selected References

Sundberg, S. D. 1986. The Systematics of Aster Subgenus Oxytripolium (Compositae) and Historically Allied Species. Ph.D. dissertation. University of Texas.

Lower Taxa

Symphyotrichum potosinum, Symphyotrichum subulatum, Symphyotrichum tenuifolium