Variation in morphological characters and habitat requirements in Carex capitata and Carex arctogena (Cyperaceae) in Norway and Sweden

Abstract

Norwegian and Swedish populations of Carex capitata s. lat. were studied for variation in morphological characters. Canonical variates analysis (CVA) arranges populations in two discrete groups, corresponding to C. capitata s. str. and C. arctogena, respectively. In principal components analysis (PCA) of the total material a small overlap could be seen. However, separate PCA: s for the two regions in Scandinavia where the two taxa are sympatric show perfect separation. Student's t‐test revealed significant differences in all morphological characters studied. Studies of companion plants, analysed with detrended correspondence analysis (DCA), indicate that the taxa have rather similar habitat demands in Oppland, Central Norway, although C. capitata s. str. seems to prefer wetter, and C. arctogena drier sites, respectively. Since the two taxa are distinct in morphology, they are best treated as separate species. The name Carex capitata is lectotypified.