Systematics and evolution of Carex sects. Spirostachyae and Elatae (Cyperaceae)

Carex sect. Spirostachyae comprises 25 species displaying the centre of diversity in Eurasia, while sect. Elatae comprises 22 species displaying the centre of diversity in tropical African mountainous regions. Phylogenetic analysis of the 136 ITS and 108 5'trnK intron sequences of 23 species of sect. Spirostachyae and 20 species of sect. Elatae revealed that neither section is monophyletic. With the exclusion of C. montis-eeka (sect. Spirostachyae) and C. insularis, C. iynx and C. longibrachiata (sect. Elatae), the sects. Spirostachyae and Elatae constitute a monophyletic group of 38 species, 22 of which were previously included in sect. Spirostachyae and 16 of which were in sect. Elatae (considering C. thomasii as C. mannii ssp. thomasii). Two main groups with different edaphic preferences were identified in the core Spirostachyae, in congruence with some morphological features. One group comprises primarily acidophilus species including 11 species of sect. Spirostachyae and 16 species of sect. Elatae. The other group includes 11 basophilic species of sect. Spirostachyae. Incongruence between nuclear and plastid genomes was detected, suggesting hybridization or lineage sorting processes in the evolution of the core Spirostachyae.