European Palaeobotany and Palynology Conference 2026

Despite representing an inherent phase in the life cycle of embryophytes, gametophytes are exceedingly rare in the fossil record compared to sporophytes. Nevertheless, such findings are critical for understanding the physiology and evolution of early land plants. The Early Devonian Rhynie chert (UK) has been instrumental in this regard, notably through the works of Remy and Remy (U. Münster) in the 1980s, who documented the first unequivocal examples from this assemblage. Over the years, additional putative gametophytes of early land plants have been described in other assemblages, including those attributed to Sporogonites, a possible bryophyte, and Cooksonia, the earliest known vascular plant. However, although widely acknowledged, the interpretation that thalloid structures represented their gametophytes remains tentative. Here, we report gametophytes preserved in organic connection with sporophytes of Sporogonites and Cooksonia from the Lochkovian compression assemblage of Impofu Dam (South Africa). Sporogonites is reconstructed as a polysetous organism comprising an axial unbranched gametophyte bearing distally multiple unbranched sporophytes. The gametophyte of Cooksonia consists in an isotomously-branched axial system terminating in multiple archegoniophores, each supporting sporophyte axes markedly narrower than the subtending gametophyte axis. These findings refute previous interpretations of the gametophytes of both taxa as thalloid structures and demonstrate that the sporophytes of the earliest land plants remained nutritionally dependent on the gametophyte. Importantly, since these taxa represent the earliest known representatives of their respective lineages, new insights into the ancestral life cycle of land plants can be provided.