Panarctic Flora

370103-04 The Papaver dahlianum aggregate P. cornwallisense, P. dahlianum

• Unassigned names:
• Papaver radicatum subsp. polare Tolm., Bot. Mater. Gerb. Glavn. Bot. Sada RSFSR 4: 87 (1923). Lectotype (LE!): Svalbard: "Spitzbergen, Advent-Bay", 05-30. July 1898, leg. Semenkevich (Egorova 1998: 101). - Papaver polare (Tolm.) Perfil., Fl. N. Kray 2-3: 131 (1936). - Papaver dahlianum subsp. polare (Tolm.) Elven & Ö. Nilsson, Nordic J. Bot. 20: 522 (2001).
• Papaver dahlianum var. hadacianum Á. Löve, Nytt Mag. Bot. 4: 14 (1955). Holotype (O!): Svalbard: Spitsbergen, Hjorthfjellet, 19. Aug. 1939, leg. E. Hadac. - Papaver dahlianum subsp. hadacianum (Á. Löve) Hadac, Preslia 32: 233 (1960).
• Papaver dahlianum var. spitsbergense "spitsbergensis" Á. Löve, Nytt Mag. Bot. 4: 14 (1955). Holotype (O!): Svalbard: Spitsbergen, Moskushavn, 01. Sept. 1939, leg. E. Hadac.

Geography: Broadly amphi-Atlantic.

Notes: The "Arctic Poppy" of Canada, Greenland, and northwestern Eurasia is among the hardiest and probably most well known of all arctic vascular plants. Three species names have been in frequent use: Papaver dahlianum (species name published 1932) on a type from northernmost mainland Norway, P. polare (published 1936) on a type from Svalbard, and P. cornwallisense (published 1956) on a type from arctic Canada. Many authors have assumed that only one species (P. dahlianum) is present (e.g., Knaben 1959a, 1959b), whereas some have considered the "Arctic Poppy" as P. polare or P. radicatum subsp. polare (incl. P. cornwallisense) and have regarded P. dahlianum as different (e.g., Rändel 1974; Kiger and Murray 1997), and a few have accepted P. cornwallisense (e.g., Porsild and Cody 1980; Petrovsky 1999).

The analyses of AFLP data (Solstad 2009) support two species as the very numerous populations sampled divide on two well separated clusters: one with populations from arctic Canada alone and including samples from the type site of P. cornwallisense, another with populations from arctic Canada, northern Greenland, Svalbard, mainland Norway, and arctic Russia and Siberia east to Taimyr, and including samples from the type sites and regions of P. dahlianum and P. polare.

The plants are largely similar in their morphological features, more similar than expected from the clear distinction in AFLP patterns. Common features are tussocks dense but not very large; blades simply divided with broad, often overlapping lobes, greyish green; scapes ascending; flowers comparatively large and with nearly equal proportions of white and yellow petals; and capsules short and broad. Comparing the sets of voucher specimens for the two AFLP clusters, differences are found especially in number of stamens (ca. 16- ca. 24 in P. cornwallisense, more than 24 in P. dahlianum) and in capsule shape (subglobular in P. cornwallisense, pear-shaped in P. dahlianum). Smaller differences are found in shape of leaf lobes and flower size (usually smaller in P. cornwallisense).

A problem is that all the assumedly diagnostic features of P. cornwallisense are found also in a large proportion of the Svalbard plants, including the Svalbard types of the names P. radicatum subsp. polare (P. polare) and P. dahlianum var. hadacianum and var. spitsbergense, whereas all the numerous Svalbard samples included in the AFLP analysis fell out in the P. dahlianum cluster. The Svalbard variation needs to be carefully re-sampled and studied molecularly before these names can be assigned. If P. polare belongs to the P. cornwallisense cluster, as morphology suggests, the name P. polare will have priority for this species. Until further we apply the names P. cornwallisense and P. dahlianum and leave the name P. polare unassigned.