Long-leaved Aster, Intermountain Aster, Western Aster
Symphyotrichum ascendens (Lindley) Nesom is widely distributed in the Great Basin (Brouillet et al. 2006; FNA). The species includes allopolyploids with 2n=26 (derived diploid) and 2n=52 (derived tetraploid) which Allen (1985) demonstrated were derived from the hybridization between S. spathulatum (x=8) and S. falcatum (x=5) yielding a new base number of x=13 only occurring in Sy. subg. Ascendentes (Rydb.) Semple.
Backcrosses to both ancestral parental species or hybrids with related taxa are sometimes seen where the ranges overlap.
1-x Symphyotrichum ascendens. 1. 1. Habit, Semple & Brouillet 4399, Nez Perce Co., Idaho. 2. Small inflorescence, Bryce Canyon N.P., 3. Heads, Utah.
Allen, G. 1985. The hybrid origin of Aster ascendens (Asteraceae). Amer. J. Bot. 72: 268-277.
Brouillet, L., J.C. Semple, G.A. Allen, K. Chambers and S. Sundburg. 2006. Symphyotrichum Nees. pp. 465-539. In Flora North America Editorial Committee, eds. Flora of North America. Vol. 20. Asteraceae, Part 2. Astereae and Senecioneae. Oxford University Press, New York.
Last revised 3 April 2025 by J.C. Semple
© 2025 J.C. Semple, including all photographs unless otherwise indicated