Two early Eocene vines from south-east England

Small diameter pyritized axes, commonly referred to as 'twigs', of fossil vitaceous and menispermaceous wood from the Lower Eocene, London Clay Formation of south-east England are described here for the first time. The vitaceous twigs, which represent the earliest known occurrence of fossil Vitaceae wood, are characterized by large diameter, solitary vessels, tall wide rays which dilate in the phloem region, scalariform intervessel pits and simple perforation plates. The wood anatomy supports a close relationship to the Vitaceae and in particular the genus Rhoicissus Planch. The menispermaceous twigs are characterized by medium to moderately large vessels, simple perforation plates, alternate intervascular pitting and very broad and high ravs. The anatomical characters support a close relationship to the Menispermaceae and in particular the genera Tinomiscium Miers and Coscinium Colebr. However, as these fossil twigs are not exactly similar to any particular genus they have been placed in the organ genus, Vitaceoxylon Wheeler and LaPasha and Menispermoxylon Vozenin-Serra, Prive-Gill & Ginsburg, with which, respectively, they have the greatest similarity. These specimens were studied using reflected light- and scanning electron microscopy. (C) 2000 The Linnean Society of London.