Abstract:This paper deals with five fossil plants which are Paradrepanozamites dadaochangensis, Thinnfeldia elegans, T. nanzhangensis, Ctenozamites difformis sp. nov., C. microloba. They were collected from the lower part of Late Triassic Jiuligang Formation in Western Hubei, while the sequence found in these plants is just coincident with the order of their evolution. Although the fertile parts of Paradrepanozamites, Thinnfeldia and Ctenozamites are unknown, the writer believes that they belong to pteridosperms, according to the present materials from Text-fig. I, it is shown that these genera have close relations in shape. From Text-fig. I, it is also revealed that these genera mentioned above have a certain law of evolution. Based on morphological variations, two directions of evolutionary trends can be recognized as follows: 1. subradiat veins without midrib→midrib but undeveloped→well-developed midrib→forming the ultimate rachis; 2. the pinnae being undivided→only little part of every pinnae being divided→most part of every one being divided→bipinnate. As it is knoum that ontogeny is a recapitulation of phylogeny. So the original shapes in different evolutionary stages of Ctenozamites may be traced by the changes of the shapes of Ctenozamites difformis sp, nov. According to the facts related above, the writer proposes the following sequence of lineage of evolution of the genera in this paper: Paradrepanozamites→Thinnfeldia→Ctenozamites.