Abstrakt
The fossil leaf material of Polenta originally described by PRINCIPI (1922, 1926) has been studied morphologically to assess the taxonomic composition of the plant assemblage and to carry out vegetation analysis. The flora of Polenta includes after the present revision 46 vascular plant taxa with 5 conifers and 41 angiosperms.
Several fossil species well known in the late Miocene sites of Italy, France and Greece have been detected. The most frequent are conifers - Taxodium dubium, Sequoia abietina, Glyptostrobus europeus, Pinus spp. and representatives of the Lauraceae - Daphnogene polymorpha, Laurophyllum sp., Platanaceae - Platanus leucophylla, Fagaceae - Fagus gussonii, Quercus psedocastanea, Q. kubinyii, Q. drymeja, Q. roburoides, cf.
Trigonobalanopsis rhamnoides, Magnoliaceae - Magnolia liblarensis, Sassafras ferretianum, Juglandaceae -"Juglans" acuminata, Pterocarya paradisiaca, Salicaceae - Populus populina, P. balsamoides, Salix sp., Ulmaceae - Zelkova zelkovifolia, Sapindaceae -Acer integrilobum, A. tricuspidatum, Leguminosae gen. div and Monocotyledonae fam. et gen div.. Noteworthy occurrences represented by one or a few samples of foliage are those of Ginkgo adiantoides, Ilex geissertii, Tilia mastajana and flower remains described as Anthites malvaeformis.
The general palaeovegetation structure of the Polenta plant assemblage corresponds to the vegetation transect of the Evaporitic Messinian with swamp, riparian vegetation, and zonal "subtropical humid forest". The results of the IPR vegetation analysis for the zonal upland vegetation indicate a transitional (ecotone) vegetation type between "Broad-leaved Deciduous Forest" and "Mixed Mesophytic Forest".
The Polenta plant assemblage shows a higher frequency of the broad-leaved deciduous elements than of evergreen and sclerophyllous, which is in contradiction to the other adjacent Messinian plant assemblages of Monte Tondo and Tossiniano.