Format: ORAL

Kyong-Sook Chung1 and Okihito Yano2

1 Deportment of Medicinal Plant science, Jungwon University, Goesan, Korea 2 Faculty of Biosphere-Geophere Science, Okayama University of Science, Okayama, Japan

Carex sect. Siderostictae is a basal lineage in the whole group of Carex. In traditional taxonomy, about thirteen taxa are considered in the group, but the recently proposed phylogeny, 27 taxa are included in the Siderosticta group. Unlike other members in Carex, the Siderosticta group has large and fewer-numbered chromosomes with distinct polyploidization (about 1 m long and 2n = 12 or 24) and miss continuous variation in chromosome number (aneuploidy, agmatoploidy and/or symploidy). The Siderosticta group has apparently broad leaves and well-developed rhizomes. Within the section, terminal spikes exhibit diversity with unisexual (staminate) and bisexual (androgynous) flowers. To clarify major lineages within the group and evaluate evolution of major characters, nrDNA (ITS and ETS), cpDNA (trnC-ycf6, aptB-rbcL, and trnL-F), and nuclear low-copy genes (catP and GZF) were utilized. nrDNA and cpDNA do not support monophyly of the traditional section and C. siderosticta, which is the most widely distributed in East Asia. However, nuclear low-copy genes support the monophyly of C. siderosticta. In addition, C. siderosticta + C. okamotoi and C. ciliatomarginata + C. splendentissima + C. pachygyna clades were well supported. Multiple polyploidization events were hypothesized in the C. siderosticta + C. okamotoi clade (2x, 3x, 4x populations). Unisexual terminal spikes are mainly found in diploids such as C. okamotoi, C. ciliatomarginata, C. splendentissima, and C. tumidula. Further discussion will be made on cytological and morphological character evolution in major lineages of the Siderosticta group.