Syn.: Aster bellidiflorus Willd., Aster lamarckianus Nees, Aster laxus Willd., Aster lanceolatus Willd., Aster paniculatus Lam. p. p., non Mill., Aster simplex Willd., Symphyotrichum simplex (Willd.) Á. Löve et D. Löve
Family: Asteraceae Bercht. et J. Presl
Distribution: Most of North America, from Yukon to northern Florida, even north Mexican states of Baja California, Chihuahua and Sonora. Two subspecies are recognized. The nominate one and S. l. subsp. hesperium (A. Gray) G. L. Nesom (in Canada and western half of US). The nominate subspecies grows more to the east and doesn’t reach Rocky Mountains. Some North American literature recognizes 5 varieties, with the nominate one is the most northern one, found in Alberta, central Quebec and in Newfoundland. The most southern one would be var. latifolium. This species has been brought to Europe and Canary Islands and also to New Zealand; it can become invasive.
Ecology: Banks of water streams, wet meadows, in the mountains, coniferous forests, from sea level to 2700 m. Where introduced, it can escape to disturbed areas where it might become invasive. Blooms from August to November.
Description: Perennial herb, 30–150(–200) cm tall. Stem erect, single, hairless or hairy. Lower leaves petiolate, oblanceolate to elliptical, 10–80 × 5–20 mm, margins toothed; stem leaves sessile, lanceolate to narrowly lanceolate, (40–)50–150 × (3–)10–20(–35) mm, margins toothed, top leaves oblanceolate to linear, 30–100 mm, margins smooth. Flower heads in an open panicle, bracts in 3–6 rows, narrowly lanceolate to linear; disc florets (13–)20–40(–52), yellow, 2.8–5.8 mm; ray florets 16–50, white to pink or bluish, 3–10(–14) mm. Fruit is an achene with pappus, about 6 mm long.
These images were taken in Canada, Alberta, Calgary, Irrigation Canal and Confluence Park (August 12 and September 22, 2013).
