Abstract: A new species of lepidodendroid fructification, Achlamydocarpon sinensis, is described from the coal-balls of the Late Permian of Wangjiazhai, Shuicheng, Guizhou, China. It differs from other species of Achlamydocarpon mainly in the sporangial wall, in which no surface layer of columnar cells is found, instead of isodiameter cells and longitudinal cells. In our opinion, the evolutionary tendency of Achlamydocarpon is as follows: (1) size of sporangia ranges from large to small; (2) walls of sporangium vary from 2 to 4 layers, and then 3, again to 2; (3) the surface layer of sporangium evolves from columnar layer to isodiameter layer and the alternative layer of isodiameter and longitudinal cells. In addition, the habitat of Achlamydocarpon is discussed.

Key words: Late Permian, Coal balls, Lepidodendroids, Achlamydocarpon sinensis sp. nov.