The Lewis B. and Dorothy Cullman Program for Molecular Systematics Studies, The New York Botanical Garden, Bronx, New York 10458 USA;
Am J Bot. 2002 Sep;89(9):1503-9. doi: 10.3732/ajb.89.9.1503.
The snap-trap leaves of the aquatic waterwheel plant (Aldrovanda) resemble those of Venus' flytrap (Dionaea), its distribution and habit are reminiscent of bladderworts (Utricularia), but it shares many reproductive characters with sundews (Drosera). Moreover, Aldrovanda has never been included in molecular phylogenetic studies, so it has been unclear whether snap-traps evolved only once or more than once among angiosperms. Using sequences from nuclear 18S and plastid rbcL, atpB, and matK genes, we show that Aldrovanda is sister to Dionaea, and this pair is sister to Drosera. Our results indicate that snap-traps are derived from flypaper-traps and have a common ancestry among flowering plants, despite the fact that this mechanism is used by both a terrestrial species and an aquatic one. Genetic and fossil evidence for the close relationship between these unique and threatened organisms indicate that carnivory evolved from a common ancestor within this caryophyllid clade at least 65 million years ago.
水轮机植物（Aldrovanda）的捕虫夹叶类似于维纳斯捕蝇草（Dionaea），其分布和习性让人联想到狸藻（Utricularia），但它与茅膏菜（Drosera）有许多繁殖特征。此外，Aldrovanda 从未被包括在分子系统发育研究中，因此不清楚捕虫夹是在被子植物中仅进化了一次还是多次。我们使用来自核 18S 和质体 rbcL、atpB 和 matK 基因的序列表明，Aldrovanda 是 Dionaea 的姐妹，而这一对是 Drosera 的姐妹。我们的结果表明，尽管这种机制既存在于陆生物种中，也存在于水生物种中，但捕虫夹是从捕蝇纸捕虫夹进化而来的，在开花植物中具有共同的祖先。这些独特而受威胁的生物之间的遗传和化石证据表明，肉食性至少在 6500 万年前就从这个石竹科进化而来。
