Doyle J A
Section of Evolution and Ecology, University of California, Davis, California, 95616, USA.
Mol Phylogenet Evol. 1998 Jun;9(3):448-62. doi: 10.1006/mpev.1998.0506.
Morphological analyses of seed plant phylogeny agree that Gnetales are the closest living relatives of angiosperms, but some studies indicate that both groups are monophyletic, while others indicate that angiosperms are nested within Gnetales. Molecular analyses of several genes agree that both groups are monophyletic, but differ on whether they are related. Conflicts among morphological trees depend on the interpretation of certain characters; when these are analyzed critically, both groups are found to be monophyletic. Conflicts among molecular trees may reflect the rapid Paleozoic radiation of seed plant lines, aggravated by the long branches leading to extant taxa. Trees in which angiosperms are not related to Gnetales conflict more with the stratigraphic record. Even if molecular data resolve the relationships among living seed plant groups, understanding of the origin of angiosperm organs will require integration of fossil taxa, necessarily using morphology.
种子植物系统发育的形态学分析一致认为，买麻藤目是现存被子植物最近的亲缘类群，但一些研究表明这两个类群都是单系的，而另一些研究则表明被子植物嵌套在买麻藤目之中。对几个基因的分子分析一致认为这两个类群都是单系的，但在它们是否相关的问题上存在分歧。形态学树之间的冲突取决于对某些特征的解释；当对这些特征进行批判性分析时，发现这两个类群都是单系的。分子树之间的冲突可能反映了种子植物谱系在古生代的快速辐射，现存类群的长分支加剧了这种情况。认为被子植物与买麻藤目无关的树与地层记录的冲突更大。即使分子数据解决了现存种子植物类群之间的关系，对被子植物器官起源的理解仍需要整合化石类群，必然要运用形态学。
