Panarctic Flora

320208-09 The Luzula arcuata aggregate L. arcuata, L. confusa

Geography: Circumpolar-alpine.

Notes: Egorova et al.: After much discussion the PAF group has reached near consensus concerning this arctic-alpine aggregate. We agree on two important points: (1) The main division runs between the circumpolar Luzula confusa and the more oceanically distributed L. arcuata s. lat. Luzula confusa has long been known as sympatric with L. arcuata in the Atlantic regions but seems to be so also in the Beringian regions. The two species differ disjunctly morphologically in Beringia, whereas transitional forms occur around the North Atlantic in eastern Greenland, Iceland, Fennoscandia, Jan Mayen, and Svalbard. The two taxa should nevertheless be treated as different species. (2) North Atlantic and North Pacific and Beringian plants of L. arcuata are widely separated geographically, The gap in North America is ca. 100 longitude, in Eurasia ca. 120. The remaining questions relate to the rank of the taxa within L. arcuata s. lat., as species or subspecies, to the variation among the North Pacific and Beringian plants, and to their relation to the North Atlantic plants.