Panarctic Flora

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520201 Chamerion angustifolium (L.) Holub

Geography: Circumboreal-polar.

Notes: Hoch: Mosquin (1966) clearly laid out a taxonomy for Chamerion angustifolium, recognizing two subspecies with morphological characters that coincide with the ploidy level difference between the two. That work was based primarily in North America. Chen (1988) extended that taxonomy to the Chinese material.

Elven: The tetraploid (functionally diploid) differs from the octoploid (functionally tetraploid) in leaf midvein glabrous vs. pubescent abaxially; leaves smaller and especially narrower vs. larger and distinctly broader; and pollen grains smaller and uniformly triporate vs. larger and mixed triporate and tetraporate. The octoploid occurs at lower latitudes and is disjunctly distributed in montane regions from the Caucasus through the Himalayas and eastern Asia to temperate North America. It is evidently different when one sees it in the field. Mosquin (1966, 1967) interpreted the octoploid to be a case of autoploidy because of strong tetravalent formation. He nevertheless treated it as a subspecies, which seems reasonable when morphologically distinguishable cytological races are acceptable as such. This was the treatment also of Hultén (1968b) who published another subspecific combination one year later than Mosquin and probably unaware of Mosquin's work. Löve and Löve (1976a) raised it to species as C. platyphyllum without clear reference to the Mosquin or Hultén treatments. We prefer treatment as two subspecies.

Higher Taxa