Biochemical Systematics and Ecology 32 (2004) 35–44 www.elsevier.com/locate/biochemsyseco Foliar flavonoids of the most primitive group, sect. Distegocarpus within the genus Carpinus Chin-Sung Chang, Jeong Ill Jeon Ã,1 Seoul National University, Department of Forest Resources and the Arboretum, 441-744 Suwon, South Korea Received 3 January 2002; accepted 4 April 2003 Abstract Foliar flavonoids in five taxa of the section Distegocarpus of Carpinus from China, Korea, and Japan were examined. Eleven compounds, mainly mono-glycosides of the flavonols myr- icetin, kaempferol and quercetin, and the flavones apigenin and luteolin were isolated and identified. The flavonoid profiles were relatively simple, but showed distinct differentiation among taxa. Flavonoid chemistry, morphological characteristics, and geographic distri- bution patterns were in accord with the idea that section Distegocarpus appeared to have dif- ferentiated into two groups from the ancestor; one group (fangiana-type) consisting of C. fangiana and C. rankanensis, and the other (japonica-type) consisting of C. cordata and C. japonica. C. japonica was considered as the most primitive extant species of the section with respect to flavonoid compounds as well as morphological characteristics. Within the fangi- ana-type, however, C. fangiana represented a more advanced than C. rankanensis only with respect to morphology. The fact that the presence of flavanone, which was a direct precursor to flavones and flavonols, was found in C. fangiana did not show correlation with the result of morphological advancement within the fangiana group. # 2003 Elsevier Ltd. All rights reserved. Keywords: Distegocarpus; Carpinus; Betulaceae; Flavonoids; Speciation; Eastern Asia à Corresponding author. Tel.: +82-312902075; fax: +82-312956660. E-mail address: carpinus@shingu.ac.kr (J.I. Jeon). 1 Current address: Department of Urban Horticulture, Shingu College, Seongnam, 462-743, South Korea. 0305-1978/$ - see front matter # 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0305-1978(03)00186-8