Panarctic Flora

370101 Papaver walpolei A.E. Porsild

• A.E. Porsild, Rhodora 41: 239 (1939). Holotype (CAN!): Alaska: Seward Peninsula, Anvil Hill, leg. A.E. Porsild 1352.

2n= (1) 14 (2x). - Far East (N), Alaska, Yukon. - At least four reports. Diploid in FCM, Solstad (2009, six plants from three localities in Chukotka, Alaska, and the Yukon Territory).
(2) 4x. - Far East (N), Alaska, Yukon. - Tetraploid in FCM, Solstad (2009, three plants from three localities together with diploids).
Not included: Löve and Löve (1975a) reported the chromosome number of P. walpolei as 2n = ca. 84 (12x), based on Zhukova and Petrovsky (1971). Petrovsky commented that the report erred in all aspects. The count was originally published as hexaploid (2n = 42), was assigned to P. lapponicum by the original authors, but it belongs to P. gorodkovii subsequently published as a new species.

Geography: Amphi-Beringian: RFE ALA.

Notes: Papaver walpolei is predominantly diploid and narrowly amphi-Beringian and is morphologically the most distinct among the arctic Papavers. It is an ecological specialist of dry limestone outcrops, screes, and gravels. Papaver walpolei is characterized by, e.g., dense tussocks with tough marcescent sheaths; leaves very small, very firm, blade mostly three-lobed with strap-shaped to narrowly spathulate lobes, rarely more lobed or very rarely simple, upper surface dark green and lower surface very pale; flowers small (but seeming large compared with the minute leaves); petals white or yellow; stamens comparatively few; and fruits very small, narrowly conical, and with a high stigmatic disc.

There is some regional morphological variation, e.g., the plants in the Yukon Territory (the Ogilvie Mountains) differ in fruit shape from those of western Alaska and East Chukotka. There are no evident differences in AFLP profiles among the populations from East Chukotka, western Alaska, or the Yukon Territory.

Sequence data (Solstad unpubl.) support the distincion of P. walpolei but indicate a connection with the central Cordilleran, predominantly diploid P. pygmaeum Rydb. These two species are distributed in non-glaciated regions, respectivelly, northwest and south of the Pleistocene Cordilleran ice sheet(s).

AFLP markers and morphological similarities both suggest that P. walpolei is most closely related to the amphi-Beringian and predominantly hexaploid P. gorodkovii.