Parallel evolution of pollination syndrome in genus of Hemerocallis : Test for introgressive hybridization hypothesis

密莲花表现出蜜蜂授粉综合征。萱草属植物叶绿体DNA的系统发育树表明，蝴蝶传粉综合征和鹰蛾传粉综合征可能是由蜜蜂传粉综合征（祖先状态）经过多次进化而来的。黄螺旋体在日本的分布表明，渐渗杂交可能是这两种综合征多重起源的主要原因。此外，三倍体物种H.fulva在日本没有变异核苷酸位点，而其他物种在每个岛屿（如本州岛、九州岛）都有几个变异位点。没有变异位点的原因可能是三倍体分类群是无性繁殖的，可能是人类转移的。

The flowers of H. middendorffii showed bee-pollination syndrome. Phylogenic tree of chloroplast DNA of genus of Hemerocallis suggested that butterflypollination syndrome and hawk-moth-pollination syndrome have probably evolved in multiple times from bee-pollination syndrome (ancestral status). The distribution of H.citrina in Japan implies that maybe introgressive hybridization acts as a main force for the multiple origins of these two syndromes. In addition, the triploid species H.fulva showed no variable nucleotide site across Japan although the other species showed several variable sites within each island (e.g. Honshu, Kyushu). The reasons why there are no variable sites might be that triploid taxon is asexually reproducing and is probably transferred by human.