Panarctic Flora

580211a Salix rotundifolia var. rotundifolia

2n= (1) 38 (2x). - Siberia (N), Far East (N), Alaska. - At least four reports.
(2) 114 (6x). - Far East (N), Alaska. - Several reports.
For the two ploidy levels, see notes.

Geography: Amphi-Beringian: RFE ALA CAN.

Notes: Argus and Yurtsev: Argus (1973) applied too wide a circumscription of Salix rotundifolia in northwestern North America, as pointed out by Yurtsev. Argus has subsequently revised the material in some North American herbaria as has Yurtsev in the Stockholm herbarium (S, e.g., Hultén's material). Numerous collections were transferred from S. rotundifolia to S. polaris but a significant part remains as S. rotundifolia with about the same geographical range as previously assumed.

Yurtsev: A separate (disjunct) extensive geographic population of the amphiBeringian S. rotundifolia has been discovered in the mountains of northeastern Yakutia (the Chersky Range) on limestone. It has proved to be diploid (2n = 38) in contrast to the amphiBeringian hexaploid (2n = 114). A small disjunct population of the same species from West Chukotka (the Anyui Mountains) was found to be diploid as well (Zhukova and Petrovsky, unpubl.). Both the western disjunct populations are morphologically indistinguishable from the typical hexaploid race.

Elven: Both diploids and hexaploids are reported from Alaska (Johnson and Packer 1968; Packer and McPherson 1974) but the occurrence of these two ploidy levels, and only these, within one species would be a unique case in northern Salix. Argus (2010) assigned the 2n = 114 counts to var. rotundifolia and the 2n = 34 counts to var. dodgeana. Some thorough morphological comparison of all available chromosome voucher material must be performed. I suspect that there still might be confusion between S. rotundifolia and S. polaris, that the former species is diploid, whereas the hexaploid counts are referable to the latter species.