Panarctic Flora

800304-06 The Veronica alpina aggregate V. alpina, V. nutans, V. wormskjoldii

Geography: North American - amphi-Atlantic - European.

Notes: The Veronica alpina aggregate is an intriguing species group where the variation and its taxonomic consequences still are insufficiently resolved. The three species accepted below are sometimes considered races of V. alpina, sometimes as two species, and sometimes as several. The aggregate consists of amphi-atlantic diploids (V. alpina with two races), Pacific diploids (V. nutans), northeastern North American and Greenlandic tetraploids (V. wormskjoldii, possibly allotetraploid from the two former), and unresolved Cordilleran diploids. For the mainly European V. alpina, see below.

Fernald (1939) divided the North American V. wormskjoldii on a fair number of varieties. Hultén (1968a, 1968b) recognized two races in North America: a wide-ranging subsp. wormskjoldii from Greenland west to Alaska and a Cordilleran subsp. alterniflora from California to Alaska where it reaches the Arctic and overlaps with his subsp. wormskjoldii. Hultén synonymized Bongard's Pacific V. nutans with subsp. wormskjoldii. However, after a ploidy variation was documented in the 1960s, the diploid northwestern North American V. nutans was accepted as apart from the northeastern North American tetraploid V. wormskjoldii (e.g., by Löve and Löve 1975a). Löve and Löve did not mention subsp. alterniflora and it is not clear whether they included all the northwestern North American diploid plants in their concept of V. nutans. The morphological differences reported between the taxa are small and partly quantitative. They are, however, fairly evident when one inspects a larger material. The two western North American taxa are morphologically more different from each other than is the western diploid subsp. alterniflora from the eastern tetraploid V. wormskjoldii s. str. It is therefore not evident that diploids and tetraploids should be divided on two species, as proposed by Löve and Löve (1975a) and followed by us. A phylogeographic study applying AFLP markers (Albach et al. 2006) throws doubts on some of our proposals but support V. wormskjoldii as an allotetraploid from V. alpina and V. nutans. This study did, however, not include the western subsp. alterniflora.