Plants (10-)70-150 cm. Stems usually simple, often with short, leafy branches proximally. Heads 20-100, in open, diffuse arrays, primary branches longer than peduncles. Involucres 5-6.2 mm. Phyllaries 30-42, sub-ulate to lanceolate, narrow, green zones narrowly lanceolate. Ray florets (23-)27-37(-42) in (1-)2 series; laminae usually white, sometimes pink, 1.9-3 × 0.2-0.5 mm, longer than pappi, drying in 1-2 coils (apices shallowly to deeply lobed). Disc florets (6-)8-15; corollas 3.4-4.4(-4.7) mm. Cypselae 1.5-2.7 mm; pappi 3.5-3.8(-4.2) mm. 2n = 10. Flowering Jul-Nov(-Jan). Roadsides, marshy habitats, often weedy; 0-1100(-4000) m; Ala., Ariz., Calif., Fla., Nev., N.Mex., Okla., Tex., Utah; Mexico; West Indies; Central America; n South America; introduced in Asia (Japan), Pacific Islands (Hawaii).
FNA 2006, McDougall 1973
Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Herbaceous annuals to biennials, to 150 cm tall, stems usually solitary, glabrous, sometimes with hairs in leaf axils, branches short, leafy, and spreading, at least above the middle, plants with taproots. Leaves: Alternate, thin, green to dark green, with ciliate margins, basal leaves ovate to oblanceolate, to 10 cm long and 1.5 cm wide, long-petiolate with sheathing bases, faces sparsely ciliate, margins entire to serrulate, cauline leaves petiolate, subpetiolate, or sessile, narrowly lanceolate or awl-shaped, the margins subentire, entire, or serrulate, not much reduced. Flowers: Heads radiate, rays white to pink, 27-37 in 1-2 series, laminae 1-3 mm long, drying in 1-2 coils, disk flowers yellow, 8-15, the lobes spreading to erect, nar-rowly triangular, glabrous, involucres cylindric, graduated, 5-8 mm high, phyllaries 30-42, graduated, lanceolate to subulate, unequal, margins hyaline, often purple-tinged, entire, apices acute, faces glabrous, heads 30-100 or more, borne in open, diffuse, paniculiform arrays. Fruits: Achenes light brown to purple, narrowly obovoid, compressed, 5-nerved, to 3 mm long, the faces sparsely stiff hairs. Pappus of numerous, white, sub-equal capillary bristles, 3.5-5.5 mm long Ecology: Found in marshy areas and roadsides, from 0-13,000 ft (0-3962 m); flowering July-November. Distribution: Alanta, Arizona, California, Flordia, Nevada, New Mexico, Oklahoma, Texas, Utah; Mexico Notes: Always found in wetlands, look to the glabrous stems; increased number of small heads; the short, leafy branches, with linear ciliate-magined leaves; the semi-short white or pink rays in 1-2 series to help identify this species. Ethnobotany: Uknown, but other species in the genus have uses. Etymology: Symphyotrichum comes from Greek symphysis for borne together and trichnos for hair, while subulatum means awl-shaped and parviflorum means small flowered. Synonyms: Symphyotrichum expansum, Aster subulatus, many others, see Tropicos Editor: LCrumbacher 2011, FSCoburn 2015