Pityostrobus yixianensis sp nov., a pinaceous cone from the Lower Cretaceous of north-east China

A silicified conifer cone was collected from Lower Cretaceous rocks in Yixi an, Liaoning Province, north-east China. The cone is long and cylindrical, and its axis contains secondary xylem with resin canals. Vascular traces to the scale and its subtending bract are separate when they diverge from the vascular cylinder of the cone axis. Where the base of the scale is separat e from the bract, resin canals are distributed adaxially and abaxially in t he vascular traces. Bracts separate from the scales marginally, and the ape x of each scale is flattened. Seeds are inverted and occur in pairs on the adaxial surface of fertile scale. Seed is winged and elliptical, lacking bo th resin cavities and vascular traces in its seed coat. The characters of t he Chinese specimen have led to the description of a new species of the fos sil genus Pityostrobus as P. yixianensis. When compared with other pinaceou s genera, P. yixianensis shows greatest similarity to the extant genera Pic ea, Pseudotsuga and Larix. It differs from other species of Pityostrobus wh ich have a close relationship with either the genus Pinus or Pseudoaraucari a. The evolutionary and phylogenetic position of Pityostrobus yixianensis i s considered to represent an ancestral intermediate between extant conifer genera such as Picea, Pseudotsuga and Larix. Pityostrobus yixianensis repre sents the first record of Pityostrobus in China and is coeval with the earl iest pinaceous cones from Europe and North America. (C) 2001 The Linnean So ciety of London.