Department of Biology, Indiana University Southeast, New Albany, Indiana 47150.
Am J Bot. 1999 Nov;86(11):1563-75.
Permineralized gigantopterid stems of Vasovinea tianii Li et Taylor gen. et sp. nov. were collected from the Upper Permian of Guizhou Province, China. They are slender and bear prickles, trichomes, and compound hooks. Internally, the stems have a sparganum cortex, eustele, and secondary xylem. The mesarch protoxylem tracheids have annular to helical thickenings, and metaxylem tracheary elements have scalariform and/or transversely elongated, bordered pits, while those of the secondary xylem have scalariform to circular bordered pits. Importantly, the inner part of the secondary xylem has large vessel elements with foraminate-like perforation plates. The hooks and other morphological and anatomical characteristics are similar to those found in gigantopterids, suggesting that Vasovinea is a member of the Gigantopteridales. The vegetative plant is reconstructed from permineralized stems and Gigantopteris-type leaves based on the anatomical similarities and intimate association. The eustele, secondary xylem, and other features support the placement of the order among the seed plants. Ecologically, Vasovinea is suggested to have been a vine or liana that used compound hooks to climb among the trees in a Permian tropical rain forest. The occurrence of vessels could have been an efficient adaptation to allow the slender stems to conduct sufficient water to the large Gigantopteris-type leaves.
中国贵州晚二叠世发现了维亚瓦西尼亚木属（ Vasovinea ）一新种——维亚瓦西尼亚木（ Vasovinea tianii ）的茎化石，它是纤细的，具有刺、毛和复钩。内部，茎具有髓射线皮层、真中柱和次生木质部。初生木质部管胞具环纹和/或螺旋加厚，次生木质部管胞具梯状和/或横长具缘纹孔，而次生木质部的管胞具梯状到圆形具缘纹孔。重要的是，次生木质部的内部分布有大型具孔状穿孔板的导管。钩和其他形态解剖特征与巨型叶植物相似，表明维亚瓦西尼亚木是巨型叶植物目（ Gigantopteridales ）的成员。维管束植物是根据解剖相似性和密切联系，从矿化茎和巨型叶型叶重建而来的。真中柱、次生木质部和其他特征支持该目在种子植物中的位置。从生态学角度来看，维亚瓦西尼亚木可能是一种藤本植物或木质藤本植物，利用复钩在二叠纪热带雨林中攀援树木。导管的存在可能是一种有效的适应，使纤细的茎能够将足够的水分输送到大型巨型叶型叶中。
