Panarctic Flora

420107-08 The Stellaria calycantha aggregate S. borealis, S. calycantha

Geography: Amphi-Pacific/Beringian - North American - amphi-Atlantic - European (N).

Notes: Rabeler (1986) and Morton and Rabeler (1989) studied the Stellaria calycantha group. Their conclusion was that S. calycantha, described from the Russian Far East, is a diploid species (2n = 26) comparatively narrowly distributed around the North Pacific, including the arctic parts of Chukotka and Alaska. Stellaria borealis, described from eastern North America, is a tetrapoid species (2n = 52) widely distributed from interior and northern Alaska eastwards through North America, Greenland, and northern Europe to the northern Urals. The ranges of the two overlap in western North America but not in Eurasia. The views of Rabeler and Morton have been followed by subsequent authors (e.g., Chater and Heywood 1993 for Europe; Cody 1996 for the Yukon Territory; Borgen and Often 2001 for northwestern Europe). Also we follow it, but with a few reservations.

Most workers before Rabeler (1986) have considered S. calycantha to be the most widespread or the only species. This makes utilization of earlier sources difficult in the area of overlap (e.g., Hultén 1944, 1968a, 1968b; Löve and Löve 1975a; Porsild and Cody 1980; Hultén and Fries 1986). More problematic is that the original material (LE) of Arenaria calycantha Ledeb. superficially resembles the northern European plant now considered S. borealis but differs from the Alaskan and Yukon Territory plant now considered S. calycantha. The same discrepancy is evident from the descriptions and illustrations in Cody (1996). We Europeans would recognize Cody's Yukon Territory S. calycantha as our S. borealis, whereas we would not recognize his S. borealis as anything we have. This matter is not resolved.