860716 Erigeron acris L.
- L., Sp. Pl.: 863 (1753). Lectotype (LINN): Europe. Herb. Linn. 994.16 (Huber 1993: 44).
2n=
(1) 18 (2x). - Europe, Siberia. - Numerous reports, a few for subsp. decoloratus.
(2) 27 (3x). - Europe (C). - Tischler (1934); Rohweder (1937).
(3) 36 (4x). - Europe (Yugoslavia). - Siljak-Yakovlev (1981).
Geography: Circumboreal.
Notes: Petrovsky (1987b) and Korobkov (PAF proposal) accepted only an undivided species. Erigeron acris s. lat. is currently treated in northwestern Europe as a complex of five parapatric to sympatric but eco-geographically and morphologically distinct races with some hybridization and possibly introgression in the meeting zones (Hämet-Ahti et al. 1986; Stenberg and Mossberg 2003; Elven et al. 2005). Three of these races do not approach the Arctic: subsp. droebachiensis (O.F. Müll.) Arc, subsp. brachypetalus (H. Lindb.) Hiitonen, and subsp. decoloratus (H. Lindb.) Hiitonen. One race reaches it according to Hultén and Fries (1986) in Norway and in several places in European Russia and Siberia: subsp. acris. One race reaches the Eurasian Arctic in general and probably even farther: subsp. politus. In our view, subsp. politus occurs, with some variation and under different names, from Fennoscandia throughout Eurasia and North America at least to Hudson Bay but is largely replaced by an amphi-Pacific and southern Beringian subsp. kamtschaticus in Kamtchatka and southern parts of Chukotka. Nesom (2004, 2006b) rather assigned all North American plants to subsp. kamtschaticus and considered it different from European-Siberian subsp. politus.
Nesom (2006b) considered var. kamtschaticus to be the Pacific and North American race of E. acris and excluded subsp. politus from North America. Nesom's separation between Eurasian subsp. politus and North American subsp. kamtschaticus needs re-evaluation. Nesom (2004: 37) did not justify the choice of subsp. kamtschaticus, instead of the older name subsp. politus, as name for the North American plant. He did not point to any character for differentiation. We therefore consider subsp. politus to be the relevant priority name also for all or the vast majority of North American plants and have entered them under that name.
Higher Taxa
- Erigeron [8607,genus]