862403d Petasites frigidus subsp. arcticus (A.E. Porsild) Cody
Distribution
Northern Alaska - Yukon: Rare
Central Canada: Rare
Shrub Tundra: Rare
Bordering boreal or alpine areas: Rare
- Cody, Canad. Field-Naturalist 108: 94 (1994). - Petasites arcticus A.E. Porsild, Sargentia 4: 74 (1943). Holotype (CAN 10,866): Canada: the Northwest Territories, the Mackenzie River Delta, East Branch, 1932, leg. A.E. Porsild. - Nardosmia arctica (A.E. Porsild) Á. Löve & D. Löve, Bot. Not. 128: 519 (1976).
Geography: American Beringian: CAN.
Notes: Subspecies arcticus is more similar morphologically to subsp. palmatus than to subsp. frigidus and subsp. nivalis. It is a fairly local taxon in northwesternmost Canada. Cody (1996) stated subsp. arcticus to be restricted to the Richardson and Mackenzie mountains. It is, however, common also farther south well into the Ogilvie Mountains and farther north along the Mackenzie River to Inuvik and beyond. It reaches the Arctic both on the coast and in the northern Richardson Mountains.
The diagnostic characters of subsp. arcticus could be interpreted as a local aberration in subsp. palmatus: subsp. arcticus has larger and less hairly leaves. Elven doubted the value of this race in 2001, after a rough survey of herbarium material (CAN, DAO), but after field experience with it in several localities in the central and northern Yukon Territory and the Northwest Territories in 2003, he considers it deserving rank. In the field, it sticks out both in general habit and in its ecology (flushes, luxuriant forests, gravelly shores, ruderal sites). In nature, no intermediates towards the sympatric subsp. frigidus or subsp. nivalis have been been observed. Bayer et al. (2006) included it in their var. palmatus. As nearly the entire range of subsp. arcticus is within the Beringian refugium, whereas the entire range of subsp. palmatus is outside, there might be a history of isolation and differentiation.
Higher Taxa
- Petasites frigidus [862403,species]