Panarctic Flora

3309021 Carex trautvetteriana Kom.

2n= 54 56 58. - Siberia, Far East (N). - Zhukova and Petrovsky (1980); Yurtsev and Zhukova (1982).

Geography: Asian (NE): SIB RFE.

Notes: Section Ceratocystis includes several morphologically similar, obviously closely related, and often hybridizing temperate to boreal taxa. Those that reach the Arctic are either considered two species - Carex flava and C. viridula s. lat. - or three or four by recognition of more species in the relationship of C. viridula. Some authors consider the North American C. viridula replaced in Europe by C. serotina (C. oederi auct.) and some related species, e.g., C. demissa. Some authors treat these plants fairly collectively (e.g., Schmid 1982, 1983, 1986; Crins 2002b, summarizing several previous works), whereas others accept more numerous taxa (e.g., Palmgren 1958, 1959; Chater 1980; Pykälä and Toivonen 1994; Hämet-Ahti et al. 1998; Elven et al. 2005).

Molecular studies (Hedrén 1996b) partly support taxonomic rank for several taxa. Other features that support the same are the eco-geographical and reproductive behavior. It is a common experience in northwestern Europe to find several morphologically separable plants of this group together in the fens, with slightly different distributions along the hydrology and pH gradients, and with transitional forms of an obvious hybrid nature, with aborting anthers and fruits (and shrunken, yellowish perigynia) as opposed to their pollen and fruit fertile assumed parents. Due to the visible sterility, hybrids are easily recognized and identified as such even between morphologically fairly similar species. The hybrids nearly always appear as single individuals but sometimes show some very local clonal growth due to short creeping rhizomes. There is no clear difference in hybrid frequency and sterility among the putative taxa, irrespective of whether they are morphologically similar (e.g., C. demissa, the non-arctic C. lepidocarpa Tausch, and C. viridula) or more different (e.g., C. flava and the non-arctic C. hostiana DC.) or whether they are considered by some authors (e.g., Schmid 1983, 1986) different species or races within a species (C. viridula, C. lepidocarpa, C. jemtlandica, C. demissa). Largely sympatric but morphologically identifiable plants at the same general chromosome number level, very often growing in more or less mixed stands or close proximity, and with sterility in their hybrids, should be accepted as species if reproductive barriers are to be a part of a species definition. See, however, Dr. Ball's comments to C. demissa and C. viridula below. We largely follow the treatment of Pykälä and Toivonen (1994).

Another question is how the relations are between the plants in northwestern Europe and those in northeastern North America. This group is broadly amphi-Atlantic. Several taxa are present on both sides with some duplicate nomenclature: C. flava, C. demissa, the non-arctic C. hostiana, the pair of C. viridula s. str. (North American) and C. serotina s. str. (European), and the non-arctic C. lepidocarpa (European) and C. viridula subsp. brachyrrhyncha (name applied in North America, European type).