610201-03 The Betula pendula aggregate B. neoalaskana, B. pendula, B. platyphylla
Geography: European - Asian & American Beringian.
Notes: The widespread European and Siberian Betula pendula approaches the Arctic in northern Europe and reaches the Borderline Arctic in northwestern Siberia. It is replaced farther east in Asia by the widespread B. platyphylla (including B. cajanderi). The closest northwestern North American parallel seems to B. neoalaskana, which might be a Beringian Pleistocene isolate from this group. The closest eastern North American associate is the non-arctic B. populifolia Marshall, according to Furlow (1997) and supported by the study of Schenk et al. (2008). The four mentioned species are known as diploids (2n = 28), as different from the mainly polyploid aggregates of B. papyrifera s. lat. and B. pubescens s. lat. Note, however, that B. papyrifera is closer to B. pendula than is B. populifolia in the molecular phylogeny proposed by Järvinen et al. (2004).
Higher Taxa
- Betula [6102,genus]