1. Graduate School of Bioresource Sciences, Akita Prefectural University, Akita: Shimoshinjo Nakano Kaidobata-Nishi 241-438, Akita, 010-0195, Japan
2. Natural History Museum and Institute, Chiba: Aoba-cho 955-2, Chuo-ku, Chiba, 260-8682, Japan
3. Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, CAS, China, 650204