Because plant fossils occur as disarticulated organs, characterizing patterns of plant evolution and phylogeny are major challenges for botanical paleontology. Therefore, to characterize the origin of gymnospermous biology, we are pursuing a long-term agenda to reconstruct, species by species, the most ancient seed plants. Tetrastichia bupatidesis a primitive gymnosperm that inhabited what is now southeastern Scotland land southern Ireland at the Devonian-Mississippian boundary (360-350 million years ago). In an intensive study of thousands of plant fragments assignable to T. bupatides conducted from 1984 through 2021, a plant reconstruction and an organismal concept for this species has been developed. This plant grew in disturbed habitats. It appears to have developed from a cotyledonary embryo and to consist of an unbranched shoot that is rooted by both a primary rooting system and adventitious roots, and that bears highly dissected fern-like fronds that bear both seed-bearing cupules and synangiate pollen producing organs. By comparison to the small number of other ancient gymnosperms that have been reconstructed from this time period, T. bupatides appears to display the pleisomorphic architecture and mode of growth for the most primitive seed plants.
Rothwell, Gar. W., M.T Dunn and A.C. Scott. 2022. Reconstructing the Tetrastichia bupatides Gordon plant; a Lower Carboniferous/Devonian (Tournaisian) hydrasperman gymnosperm from Oxroad Bay, Scotland and Ballyheigue, Ireland. Review of Palaeobotany and Palynology. 10.1016/j.revpalbo.2021.104551