A Miocene sedge from Hungary

PUBLICATION — Halamski, A.T., Kraski, J., Erdei, B. & Durska, E. 2025. Rhizome and leaf anatomy of Rhizocaulon huberi H.-J. Gregor (Cyperaceae, Miocene) and nomenclature of the genus Rhizocaulon Saporta ex Schimp. et Schenk. Acta Geologica Polonica, 75 (4), e64. doi: 10.24425/agp.2025.157029

Figure: Rhizocaulon huberi. The bottom image (C) shows the silicified rhizome physically connected with the pseudostem. The top left image (A) shows a transverse section of the pseudostem, and the top right one (B) its enlargment, showing the anatomy of leaves forming the pseudostem.

The authors performed a taxonomic revision (in other words, a restudy) of silicified plant remains from the Miocene of Tokaj Mountains (Hungary). These are rhizomes, roots, and pseudostems, classified as Rhizocaulon huberi H.-J.Gregor. Using newer study methods, unavailable to the authors of the first description (the protologue), allowed classifying the fossil plant within the sedge family (Cyperaceae). The extant South American genus Diplasia is the most similar. The paper also addresses the question of the validity of the use of the genus name Rhizocaulon by earlier authors; such analyses, although tedious, are necessary for the stability of biological nomenclature.