Yujin Jeon1P, Heewon Ji1, Yeonchan Kang1, Bo-Mi Nam2, and Jun-Ho Song1

1Department of Biology, Chungbuk National University, Cheongju, Korea;

2Division of Botany, Honam National Institute of Biological Resources, Mokpo, Korea

The genus Mercurialis L. (Euphorbiaceae) comprises eight species worldwide and has been widely used as a model system for studying sexual systems and plant evolution. Mercurialis leiocarpa Siebold & Zucc. is mainly distributed in East Asia, including Korea, and is native to the southern regions of Korean Peninsula. Although European-Mediterranean species, such as M. annua L., have been extensively studied, comprehensive investigations of the East Asian species M. leiocarpa remain lacking. In this study, we conducted a detailed examination of the external morphological and micromorphological characteristics of M. leiocarpa and documented representative external features through descriptions and photographic plates. Our results indicate that Korean populations of M. leiocarpa exhibit trioecy, with monoecious and dioecious individuals occurring simultaneously. Micromorphological traits of leaves and pollen grains were analyzed using scanning electron microscopy to assess intersexual morphological differences, revealing distinct variations in pollen and other micromorphological features among sexual forms. To further elucidate these findings, additional studies on the reproductive biology and phylogeny of M. leiocarpa, including sex ratio, sexual function, ploidy levels, and pollination biology, are required.

* This work was supported by a grant from the Honam National Institute of Biological Resources (HNIBR), funded by the Ministry of Climate, Energy and Environment (MCEE) of the Republic of Korea (Grant No. HNIBR202101107).