1. Department of Biology, Chungnam National University, Daejeon 34134, Korea
2. Nakdonggang National Institute of Biological Resources, Sangju 37242, Korea
3. School of Life Science, Kyungpook National University, Daegu 41566, Korea
4. Department of Botany, Connecticut College, 270 Mohegan Ave., Box 5604, New London, Connecticut 06320, USA