摘要
迄今为止世界上最早的种子植物发现于北美和欧洲西北部的晚泥盆纪地层。这些种子植物可能起源于前裸子植物，即解剖构造上较为进化的一类蕨类植物。然而，从目前的证据来看尚无法确切判断这些种子植物起源于前裸子植物中的某个特定类群，比如古羊齿目和戟枝木目。作者总结了种子植物祖先的有关证据，并对目前已知的最早的种子植物的形态进行了概述。由于种子植物自出现起即表现出丰富的形态多样性，因而尚无法对某个可能的祖先形态作出判断。目前的研究尚不能确切回答种子植物起源的全部问题，仍需寻找有关前裸子植物与种子植物过渡类型的新证据。
The earliest identified seed plants are found in Latest Devonian aged sediments from Northwest Europe and North America and are believed to have evolved from within the progymnosperms, a group of anatomically advanced pteridophytic plants. However, current evidence makes it problematic to determine from which particular progymnospermous lineage the seed plants evolved, with the major contender being the Aneurophytalean progymnosperms. The evidence for the ancestral stock to the seed plants is summarised and the morphologies of the earliest known seed plants are considered. From their first geological occurrence, the seed plants are morphologically diverse to such an extent that the identification of a single potential ancestral morphology is impossible. In the light of the evidence so far presented, the precise origin of the seed plants is unresolved and in need of new evidence relating to the progymnosperm/seed plant transition. Future lines of research are also suggested.
