Panarctic Flora

342011 Calamagrostis tenuis V.N. Vassil.

• V.N. Vassil., Bot. Mater. Gerb. Bot. Inst. Komarova Akad. Nauk SSSR 8: 66 (1940). Holotype (LE): Russian Far East: South Chukotka, the Anadyr basin, west of the Rarytkina range, 13. Aug. 1933, leg. V. Vassiljev 1619. - Calamagrostis angustifolia subsp. tenuis (V.N. Vassil.) Tzvelev, Novosti Sist. Vyssh. Rast. 1965: 37 (1965). - Calamagrostis purpurea subsp. tenuis (V.N. Vassil.) Tzvelev, Novosti Sist. Vyssh. Rast. 32: 182 (2000).

2n= 28 (4x). - Far East (N, S), Alaska. - Numerous reports, 46 counts from Alaska alone.
These are reports under the names C. angustifolia, C. canadensis, C. langsdorffii, C. purpurea, and C. tenuis. Several reports of tetraploids from eastern Asia, for C. angustifolia or C. angustifolia subsp. angustifolia, may belong to more southern taxa.

Geography: Asian (NE) - amphi-Pacific/Beringian: SIB RFE ALA.

Notes: In our current concept, Calamagrostis tenuis encompasses the sexual tetraploids in northeastern Asia and northwestern North America, the latter traditionally included in C. canadensis or C. langsdorffii (also by Soreng and Greene in Soreng et al. 2003 and by Marr et al. 2007). Tzvelev (1964a) included several more local species (among them C. tenuis) in an extended C. angustifolia but this complex as described included in addition to tetraploids also hybrids and probably some agamosperms. Probatova (1985) considered C. tenuis specifically distinct from C. angustifolia Kom., Bot. Mater. Gerb. Glavn. Bot. Sada AN SSSR 6: 1 (1926) holotype (LE): Russian Far East: the Primorsk area, 30. June 1913, leg. A. Bulavkina 109, the latter a comparatively southern taxon in the Russian Far East and replaced by C. tenuis in Kamtchatka, the Magadan region, and in Chukotka. This is the main reason why we have chosen to apply the name C. tenuis for the northern sexual tetraploids.

Mitchell (1968) showed that it is possible to distinguish morphologically between tetraploids and high-polyploids on the North American side. From morphological evidence (especially Mitchell 1968), it is probable that the amphi-Pacific/Beringian tetraploid(s) have furnished a major part of the genome in the high-polyploid C. canadensis-langsdorffii. As C. canadensis-langsdorffii is very polymorphic and may have received genetic material from other sexuals, at least in other areas (e.g., from C. purpurea in Asia), we keep C. tenuis and C. canadensis-langsdorffii apart at species level.

Two morphologically different tetraploids may be present in the Beringian areas. The pollen-fertile and tetraploid plants of south-central and southwestern Alaska are tall-grown and superficially similar to the pollen-sterile and high polyploid C. canadensis. In western Alaska (the Seward Peninsula, several localities, ALA) and East Chukotka (O) occurs a more slender and small-grown pollen-fertile plant that conforms better to Asian C. tenuis. It is morphologically different in several features both from the southern tetraploid and from the high-polyploid C. canadensis-langsdorffii.