Origins of the disjunct distribution of the Estuarine sedge (Carex recta)

Mary Dean

The estuarine sedge is a rare plant in Britain, being restricted to three sites in the north-east of Scotland. It is considered a species of hybrid origin, the result of a cross between the C. aquatilis and C. paleacea, although the latter does not occur in the UK. C. recta is also recorded from the Eastern seaboard of the USA and Canada and records also exist of Scandinavian examples. It seems likely that these latter records are due to taxonomic confusion of C. recta with other hybrid offspring of C. paleacea and other members of the section Phacocystis within the Carex genus.

The question of the disjunct distribution of C. recta still remains. Using morphometric, anatomical and isozyme methods, this project aims to identify whether this amphiatlantic distribution is due to long distance dispersal or multiple evolution. In addition it is hoped to resolve some of the nomenclatural difficulties of the Scandinavian hybrid taxa that have C. paleacea as a putative parent (eg C. salina and C. halophila).

Conference Presentations

Dean, M and Ashton, P. A. (2000) ‘Evolutionary studies on Carex recta Boott, the estuarine sedge.’ Poster presentation: Ecological Genetics Group Annual Conference. Edge Hill.

Dean, M and Ashton, P. A. (2002) ‘Investigating hybridisation in the genus Carex.’ Oral presentation: Ecological Genetics Group Annual conference. Newcastle.

Dean, M. and Ashton, P. A. (2006) ‘A reassessment of the distribution of Carex recta Boott (Cyperaceae) in the British Isles’. Watsonia 26: 31-39.