Science. 1969 Apr 18;164(3877):295-6. doi: 10.1126/science.164.3877.295.
Plant fossils from Lower Permian strata of the southwestern United States have been interpreted as cycadalean megasporophylls. They are evidently descended from spermopterid elements of the Pennsylvanian Taeniopteris complex; thus the known fossil history of the cycads is extended from the Late Triassic into the late Paleozoic. Possible implications of the Permian fossils toward evolution of the angiosperm carpel are considered.
美国西南部下二叠统的植物化石被解释为苏铁类大孢子叶。它们显然是宾夕法尼亚系 Taeniopteris 复合体中生有精子器的鳞木类的后裔；因此，已知的苏铁类化石历史从晚三叠世延伸到了晚古生代。还考虑了二叠纪化石对被子植物心皮进化的可能影响。
