500731 Saxifraga adscendens L.
- L., Sp. Pl.: 405 (1753). Lectotype (UPS): Europe. Herb. Burser XVI (1):89 (Aldén and Strid in Strid and Tan 1986: 367). - Muscaria adscendens (L.) Small, N. Amer. Fl. 22, 2: 129 (1905).
2n=
22 (2x). - Europe (N, C). - Several reports, e.g., Knaben (1954, central Norway) for subsp. adscendens.
Geography: European & Cordilleran.
Notes: Zhmylev: Saxifraga adscendens is an amphi-Atlantic boreal species of considerable morphological variability. Dwarfish plants with relatively broad leaves and narrow petals are distinguished by North American botanists as a subspecies. Webb and Gornall (1989) stated that plants with such characters are met with practically in all the distribution area of this species.
Elven and Murray: The same argument is forwarded by Brouillet and Elvander (2009b) but we do not agree. Saxifraga adscendens is not amphi-Atlantic as it is missing from Atlantic North America. It has two-part areas: one in Europe and the Caucasus, another in the Cordilleras of western North America. The two areas are separated by ca. 120-130 longitude from western North America east to Europe and ca. 160 from the Caucasus east to western North America. The disjunction is probably old and a subspecific differentiation would be expected in a possibly rapidly evolving biennial species. After comparing European and western North American plants, in the field and the herbaria, we are in no doubt that they are different enough morphologically to merit rank at least as races. A western North American race is entered below. The European one (subsp. adscendens) reaches northern Norway but not the Arctic.