A study of the large Silurian land plant Tichavekia grandis Pšenička et al. from the Požáry Formation (Czech Republic)

The recently described fossil plant Tichavekia grandis from the upper Silurian of the Barrandian area (Czech Republic) contributed to our understanding about the early land plant diversity, but it raised also many questions. Megafossils, preserved as coalified compressions, come from the Kosov Quarry near Beroun from the Požáry Formation of Neocolonograptus parultimus – Neocolonograptus ultimus Zone, which corresponds to the Přídolí (Series Pridoli sensu the ICS). The increased branching and the spectacular size, reaching 13 cm in height, makes this plant exceptional compared to other Silurian plant taxa. This paper presents a detailed morphological study of the Tichavekia grandis type material. Completeness of the specimens allows a precise idea of the appearance of the living plant and provides us with more information on its possible habitat and palaeoecology. Although many morphological features suggest a possible vascular nature of the plant, anatomy is not preserved. The affinity of an associated enigmatic circular structure with the plant is also discussed here.