Panarctic Flora

50 Saxifragaceae

Notes: Dr. P.Yu. Zhmylev has commented extensively on the species of Micranthes and Saxifraga.

Zhmylev: The sections of Saxifraga s. lat. are for the most part morphologically distinct and have repeatedly been considered as different genera (Haworth 1812, 1821; Small and Rydberg 1905; Löve 1983b, 1984a etc.). This modular character of Saxifraga is partly confirmed by genetic investigations (Soltis et al. 1996). Nevertheless, the majority of botanists still consider the genus Saxifraga in a broad sense.

Elven and Murray: The phylogenetic analyses of Soltis et al. (1996, 2001) and later works show that there are two major branches of genera in Saxifragaceae. A major segregate of traditional Saxifraga, i.e., the Micranthes group together with, e.g., Chrysosplenium, belongs in a different main branch from that of Saxifraga s. str. The molecular evidence makes it impossible to retain Micranthes within Saxifraga and we accept a genus as done by Brouillet and Gornall (2007) and Brouillet and Elvander (2009a). The genus name has been changed from Saxifraga to Micranthes in Zhmylev's notes.

Zhmylev: Infraspecific variation of several arctic saxifragas incl. [Micranthes] is still in need of special investigations and discussions, first of all the taxonomic status of races in such polymorphic taxa as Saxifraga cespitosa s. lat. or S. rivularis s. lat. the latter now revised. In other cases, such as Saxifraga bronchialis s. lat. and Micranthes davurica s. lat., there are different views of whether a complex constitutes one wide species with several subspecies (usually the North American and European opinion) or a series of more or less closely related species (usually the Russian opinion). In these cases taxa are mostly accepted at the rank of species by me but lumped into polymorphic complexes (aggregates).

Elven and Murray: We are in doubt whether the numerous species proposed by Zhmylev in some aggregates can be justified at that rank. However, we do not have the necessary experience with many of the proposed and named taxa, especially not the Russian ones, to formulate and argue for an alternative. Zhmylev's proposals in most parts of Micranthes and Saxifraga are therefore accepted but with some notes.