830401 Mertensia maritima (L.) Gray
- Gray, Nat. Arr. Brit. Pl. 2: 354 (1821). - Pulmonaria maritima L., Sp. Pl.: 136 (1753). Lectotype (BM-000557936): the British Isles. Herb. Clifford: 48, Cerinthe 3 (Selvi in Cafferty and Jarvis 2004b: 803).
Geography: Amphi-Pacific/Beringian - North American (N) - amphi-Atlantic.
Notes: We accept three races within Mertensia maritima. Subspecies maritima is amphi-Atlantic and reaches the Arctic in Iceland, mainland Norway, the Murman area, and approaches in Labrador. Subspecies asiatica is amphi-Pacific, not yet fully confirmed to reach the Arctic (see below), but plants transitional towards subsp. tenella are found in the Arctic in southwestern Alaska, perhaps also in South Chukotka. Subspecies tenella is arctic and morphologically well distinct from both the preceding races by several differential characters vs. subsp. maritima (Elven et al. 2005; Skarpaas et al. 2007). Subspecies tenella has leaves with blade broadly spathulate and apex rounded or obtuse with a short point, calyx segments ovate to narrowly cordate, not much enlargening during fruit maturation (ca. 2 x 1 mm), and corolla 4-5 mm long with segments rounded with apex obtuse or subobtuse. Subspecies maritima has leaves with petioles relatively short, blade ovate with apex subacute to slightly acuminate, calyx segments triangular, becoming distinctly larger during fruit maturation (ca. 3.5 x 2.8 mm) and broadly cordate and acuminate, and corolla 5-6 mm long with segments triangular to cordate and acute. Subspecies tenella is found in Svalbard and Jan Mayen, Greenland, arctic Canada, arctic Alaska, and in the arctic Russian Far East west to the Kolyma River.
Subspecies tenella differs from the North Atlantic subsp. maritima also in molecular markers. Skarpaas et al. (2007) found uniformity in isoenzymes in subsp. maritima from southernmost to northernmost Norway and differences from arctic (Svalbard) material of subsp. tenella.