Two early Eocene vines from south-east England

Abstract

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 rays. 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, Vitacexoylon Wheeler and LaPasha and Menispermoxylon Vozenin‐Serra, Privé‐Gill & Ginsburg, with which, respectively, they have the greatest similarity. These specimens were studied using reflected light‐ and scanning electron microscopy.

Systematics of Vitaceae from the viewpoint of plastid rbcL DNA sequence data

“…There is also some morphological support for Rhoicissus appearing near Ampelopsis . Rhoicissus is a relatively small African genus today but has been recorded from the Lower Eocene of England (Poole & Wilkinson, 2000). They are generally more slender plants than species of Ampelopsis and have cymose inflorescences, which often bear tendrils.…”

“…Wikström et al (2001) calibrated the phylogenetic tree of Soltis et al (2000) using the molecular clock approach of Sanderson 1997; nonparametric rate smoothing), and these results showed that Vitaceae are potentially as old as 108–117 ± 4 Myr (the age of the split between Vitaceae and the rest of the rosids) with the crown group (the split between Leea and the rest) dated to 78–92 ± 5 Myr. Extant genera, including Vitis and Rhoicissus , have been described from the Early to Middle Tertiary (up to 65 Myr ago; Wheeler & Lapasha, 1994; Poole & Wilkinson, 2000). However, from strata of a similar age genera combining the features of extant genera have also been described (Tarasevich, 1984; Cevallos‐Ferriz & Stockey, 1990).…”

Seed morphology of modern and fossilAmpelocissus(Vitaceae) and implications for phytogeography

“…Although fossil pollen grains have sometimes been assigned to extant genera of the Vitaceae, (Muller, 1981;Ferguson et al, 1998;Nemejc et al, 2002), the criteria used to distinguish these pollen grains from those of other angiosperm families with similar pollen have not been clearly indicated. Occasional permineralized stems have contributed to our knowledge of the Vitaceae fossil record through careful comparison with the stem anatomy of extant representatives, but these reports are relatively rare (Watari, 1951;Prakash and Dayal, 1964;Wheeler and Lapasha, 1994;Poole and Wilkinson, 2000;Wheeler and Manchester, 2002).…”

The first record of fossil Vitaceae wood from the Southern Hemisphere, a new combination for Vitaceoxylon ramunculiformis, and reappraisal of the fossil record of the grape family (Vitaceae) from the Cenozoic of Australia

“…4.2 Generic limits and variation in the wood anatomy of fossil Vitaceae wood Wheeler & La Pasha (1994) provided anatomical information for most modern genera in the Vitaceae. Vitaceae wood can be identified by a combination of features, such as the presence of wide, solitary vessels, scanty paratracheal parenchyma, very wide and tall rays, storied or irregularly storied axial elements, stratified phloem (fibre bands alternating with sieve tubes and axial parenchyma), and conspicuous ray dilatation in the phloem forming wedges towards the periderm (Wheeler & La Pasha, 1994;Poole & Wilkinson, 2000). As there is considerable, and phylogenetically informative characters in the wood anatomy of the Vitaceae (Poole & Wilkinson, 2000; Table 1), we, here, recognise two new fossil wood genera that display features of Vitaceae, but possess a combination of distinctive features that warrant separate generic status ( Fig.…”

“…Type species Stafylioxylon ramunculiformis Stratigraphy London Clay Age Late Eocene (Ypresian) (Collinson & Cleal, 2001) Remarks Poole & Wilkinson (2000) interpreted the wood anatomy of S. ramunculiformis as indicating a close relationship to Rhoicissus. The combination of characters seen in S. ramunculiformis; i.e., non-stratified phloem, scalariform intervessel pits and heterocellular rays do suggest links with Rhoicissus.…”