Biosystematic Studies of Carex (Cyperaceae) IV. Phylogenetic Analysis and Infrageneric Classification of the Basal Lineages of C. subg. Carex

Abstract

Carex (Cyperaceae) is a diverse genus with approximately 2, 150 species. Recent molecular studies showed that, although the genus has a nearly cosmopolitan distribution, East and Southeast Asia is the cradle of its diversification. They further showed that Carex comprises six subgenera, among which subg. Carex is the largest in number of species. Despite these studies, the relationships and classification of basal lineages within subg. Carex remain unresolved, owing to their considerable morphological diversity and limited sampling of Asian plants in previous molecular studies. This report is based on a comprehensive phylogenetic analysis of the basal lineages within subg. Carex that used extensive chloroplast CDS data (70 loci, 58, 601 bp) obtained from samples collected in Japan, China, Thailand, and the Himalaya. Based on the phylogenetic results as well as an examination of eleven morphological characters, seven sections, Albae, Decorae, Dissitiflorae (a new section for C. dissitiflora and C. bostrychostigma), Filicinae, Graciles, Indicae and Mundae are recognized as basal monophyletic lineages in subg. Carex. In the phylogeny of subg. Carex, Dissitiflorae occupied the most basal position with 100% bootstrap support. A clade (100%) comprising Albae-Graciles subclade (100%) and Indicae-Mundae subclade (100%) diverged as the next branch, followed by the Decorae-Filicinae clade (100%) and the Core subg. Carex clade (84%).