The whole plant concept of Reevesia from the Neogene of the Bełchatów Lignite Mine (central Poland)

Abstract

Integration of isolated parts of fossil plants into one plant is one of the most important goals in the whole-plant reconstruction concept in paleobotany. Three fossil-species, Laria rueminiana (Heer) G. Worobiec & Kvaček (leaves), Reevesia hurnikii Kvaček (the capsule valve of fruit), and Reevesiapollis triangulus (Mamczar) Krutzsch (pollen grains), related to the extant genus Reevesia Lindl, were found in one fossil assemblage in the upper Miocene deposits of the Bełchatów Lignite Mine (central Poland). In early Miocene locality of Bílina, Czech Republic the listed taxa were also accompanied by fossil seeds of Saportaspermum Meyer & Manchester. The co-occurrence of them suggests that they might represent vegetative and reproductive organs of a single biological species. Besides the co-occurrence of these fossil-taxa, the affiliation of the discussed detached fossil plant organs in the whole-plant reconstruction of the Reevesia plant could be indirectly proven using their similar systematic affinities (recent relatives), and the discovery of ex situ pollen aggregations (clumps) of Reevesiapollis triangulus in one of the cuticular slides of leaves of Laria rueminiana. These clumps surely were attached to the surface of the Laria leaf. Similar to the nearest living extant relatives, the Reevesia plant thrived in a warm temperate and humid climate with mild winters (a Cfa climate type according to the Köppen-Geiger climate classification) and was usually a component of riparian vegetation also growing in drier, mesophytic plant communities.