NOTES ON CAREX FLAVA AND ITS ALLIES 



IV— GEOGRAPHIC DISTRIBUTION* 

 By Elizabeth W. Davies 



University College of Leicester 



Detailed information about the world distribution of the C. flava aggregate is rather 

 fragmentary. However, in spite of the group being represented in both hemispheres, as 

 a whole it seems to have circumboreal tendencies and the members were described by 

 M. Raymond in 1951 as amphi-atlantic species. Although they are found on both 

 sides of the Atlantic Ocean their European distribution is usually more extensive than 

 their American one (Fig. 1). The British representatives are clearly components of the 

 Northern European flora, and are rare in the Mediterranean region, where C. mairii 

 Coss. & Germ, and C. durieui Steud., two closely allied species, seem to replace them, 

 and are locally abundant. 



C. flava is a plant with oceanic tendencies, but although it is scattered locally 

 throughout Eurasia it is absent in the Mediterranean region. It occurs in Central Europe, 

 extending to Iceland and Lapland in the North, and is to be found occasionally in the 

 mountainous regions of Scandinavia, the Alps, and the Auvergne in Central France. Its 

 eastern limits are Russia, where it is fairly common in the North, and in the west Caucasus, 

 while it has been doubtfully recorded from near Lake Baikal. In contrast, however, this 

 species is pronouncedly continental in North America, and extends throughout Canada, 

 as far as British Columbia and Vancouver Island. 



C. lepidocarpa, unlike the last species, has not a boreal circumpolar distribution, but 

 is a more abundant species in Central Europe. This sedge, which is very rare in southern 

 Europe, is distributed from Central France, Switzerland and Germany northwards to 

 the Arctic Circle, but only extends to Finland, north-west Russia and the Balkans in 

 the east, and to Newfoundland, Quebec, and the Magdalen Islands in the Gulf of St. 

 Lawrence in eastern Canada in the west. 



Likewise the commonest British species, C. demissa, has a limited distribution 

 outside northern Europe. This sedge extends from Scandinavia and Finland southwards 

 to North Spain and Portugal, but is totally absent from Russia, unless the Russian species 

 C. flavella Krecz. is conspecific with it. In North America, C. demissa is described as 

 a relic Atlantic species, and is only recorded from the maritime regions of Quebec and 

 New Brunswick and some of the islands in the Gulf of St. Lawrence, where the flora is 

 Atlantic in character. This species seems to be the only member of the aggregate known 

 from Greenland. 



In contrast to C. demissa, C. serotina, a rather local plant in the British Isles, is the 

 most abundant member of this group, with a rather scattered distribution. Thus, this 

 species, which appears to be a relic with a much wider distribution in the past, occurs 

 in lowland and open habitats throughout Europe, Siberia as far as Lake Baikal, Turkestan, 

 Iran, and North Africa, Madeira and the Azores. Reports of its occurrence from New- 

 foundland and the Magdalen Islands are doubtful and still need confirmation, for these 

 records are probably really C. viridula Michx. The characters separating these two 

 species are still obscure, although it seems likely that they are worthy of specific rank. 



• Part of a thesis approved for the degree of Ph.D. by the University of London. 



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