Taxonomy of the <i>Carex flava</i> complex (Cyperaceae) in North America and northern Eurasia. I. Numerical taxonomy and character analysis

Abstract

The patterns of variation in morphological characters of the North American and northern Eurasian members of the Carex flava group (section Ceratocystis) have been examined using principal components analysis and discriminant analysis, with the aim of elucidating the phenetic relationships of these taxa. Taxa that have been reported to occur on both land masses have been compared, and in all such cases, the multivariate numerical analyses have shown them to be taxonomically identical. Additional micromorphological and ecological characters have also been examined in several taxa within the complex. Achene silica body ornamentation presents a trend toward increasing elaboration with evolutionary advancement. Analyses of soil macronutrients and acidity suggest that North American C. flava L. is a calciphile, as it is in Europe, while C. cryptolepis Mack. is a calcifuge. The infraspecific taxa within C. viridula Michx. vary in their soil preferences, or are generalists. On the basis of the morphometric, micromorphological, and ecological analyses, three distinct species (C. flava, C. cryptolepis, and C. viridula) are recognized within this complex, the last containing six infraspecific taxa. They are formally treated in the second part of this series.