Panarctic Flora


342008 Calamagrostis lapponica (Wahlenb.) Hartm.


Geography: Circumboreal-polar.

Notes: A recent survey (2008-2009) of northern European and North American material (ALA, BG, O, TRH, TROM) makes us wonder what Calamagrostis lapponica is and how it should be circumscribed and possibly subdivided. It is either a complicated species or a group of species. Nygren (1946) suggested C. lapponica to be one or more apomictic derivatives from the mainly tetraploid and sexual C. neglecta, possibly also involving other species. This hypothesis was supported by Greene (1980, 1984) and by Tzvelev (in comment). There are at least three aspects that count against an origin from C. neglecta alone: reports of tetraploids also within C. lapponica s. lat. (see below), several morphological features (with no overlap with tetraploid C. neglecta), and preference in C. lapponica for very different sites, mainly acidic, dry, grassy or ericaceous heaths and forests vs. circumneutral to basic, rich fens, swamps, and shores for C. neglecta s. lat. We have found northern European C. lapponica and C. neglecta to differ disjunctly (in many characters) but we accept that this line is more problematic to draw in the material from northern North America.

Russian authors, including Tzvelev (PAF proposal and elsewhere), accept two species or subspecies: a mainly arctic and very high-polyploid subsp. lapponica, and a mainly boreal and more low-polyploid subsp. sibirica (C. sibirica, including C. lapponica var. groenlandica and var. nearctica). The gap in the ploidy levels is appreciable. The very numerous chromosome counts are either at (4x-)6x(-7x) for subsp. sibirica or at (12x-)16x(-20x) for subsp. lapponica. These taxa have not been considered by North American or northwestern European authors until recently. Soreng and Greene in Soreng et al. (2003) and Marr et al. (2007) recognized only one species without subdivisions for North America.

Elven et al. (2005, 2010) revised the Norwegian and some northern Swedish and Finnish material into two groups differing in some morphological features, in ecology, and in geographical ranges, but ploidy levels in this herbarium material are and probably will remain unknown. The material which conforms morphologically to the presumed low-polyploid subsp. sibirica differs more from the (mainly) tetraploid C. neglecta (see the hypothesis above) than that which conforms to the presumed high-polyploid subsp. lapponica. If C. neglecta is involved in the parentage of C. lapponica s. lat., morphology suggests that it is involved in subsp. lapponica but probably not in subsp. sibirica. For these reasons we are ready to accept two taxa, as races or species. An argument for races is that the differences are few, for species that the taxa are largely sympatric and not connected by any obvious transitions (and the intermediate ploidy levels of 8x-11x are not documented). There are, however, three arguments against recognition of two species: (a) There is yet little documentation for the presumed correlation between morphology and ploidy levels. (b) We do not know whether there is a discontinuity in the morphological differences throughout, even if the differences in the Fennoscandian material are distinct (albeit few). (c) We have found the same criteria much more difficult to apply on northwestern North American material. And (d), both the proposed races (and ploidy groups) are reported (by Tzvelev) to occur more or less in parallel from northern Fennoscandia throughout European Russia, Siberia, and North America to northeastern Canada. However, if a correlation between morphology and ploidy level(s) could be documented throughout this wide range, it would support rank as two species rather than races as would the suggested background in different parental combinations if that hypothesis could find molecular support. A rough survey of a northwestern North American material (ALA) in 2009 revealed very little obvious subsp. sibirica (based on the Russian and Scandinavian morphological criteria).

Wahlenberg's Arundo lapponica was described and with designated lectotype from northern Finland (boreal), where both hexaploids and high polyploids are well documented (Nygren 1946), and where from morphological evidence both subsp. lapponica and subsp. sibirica occur. The type specimen (UPS) is in good condition and shows the large, long-branched panicle and some other panicle features conforming to subsp. sibirica but the perhaps more important leaf features conforming to subsp. lapponica.

The ranges of the two taxa are not clear. The low-polyploids (4x-7x, presumably subsp. sibirica) are documented from northern Fennoscandia, European Russia, Siberia, the Russian Far East, Canada, and Greenland. The high-polyploids (12-20x, presumably subsp. lapponica) are documented from southern and northern Fennoscandia, European Russia, Siberia, the Russian Far East, Alaska, and Canada (but not from Greenland). In northernmost Fennoscandia, morphologically defined subsp. lapponica reaches the Arctic, whereas subsp. sibirica is restricted to the boreal valleys. The regions reported by Tzvelev's (PAF proposal) for the two proposed races are tentatively accepted but have been revised for Fennoscandia.

Higher Taxa