Flower longevity and 13 external morphological characters were measured and compared with a molecular phylogenetic tree obtained from the nucleotide sequences of three noncoding chloroplast regions, the rbcL-atpB intergenic region, the trnL (UAA) intron, and the spacer region between trnL (UAA) 39 exon and trnF (GAA). We found evolutionary changes not only in qualitative traits but also in quantitative traits.

Results from the molecular phylogenetic analyses showed that H. citrina var. vespertina did not form a monophyletic group; that clades in the molecular tree contained both species, indicating that Japanese H. citrina var. vespertina had multiple origins and originated from at least three different lineages that invaded the Japanese Archipelagoes separately through different routes; and that evolutionary adaptation for flower longevity occurred in parallel. Based on morphological, phenological, and molecular analyses, we suggest that pollinator-mediated evolutionary changes in floral characters were accompanied by adaptive evolution for flower longevity.
Keywords: Hemerocallis, phylogeny, evolution, morphology, noncoding chloroplast DNA.