Search Results

Koelreuteria yuanmouensis sp. nov. (Sapindaceae) is described from the Pliocene fluvio-lacustrine rocks of Hutiaotan Earth Forest, Yuanmou Basin, Yunnan, China. This is the first report of fossil Koelreuteria wood from Asia. The history of the genus is reviewed. Fruits and leaves of the genus have been reported from the Paleocene onwards in Asia, North America, and Europe, with the genus becoming restricted to East Asia during the Neogene.

In: IAWA Journal

This paper describes the first record of Peltophoroxylon (Ramanujam) Müller-Stoll et Mädel 1967 from the late Pleistocene of Argentina. The fossil specimens were recovered from the Colonia Ayuí and Punta Viracho fossil localities of the El Palmar Formation, located in the middle part of the Uruguay Basin, eastern Argentina. The diagnostic features are: growth ring boundaries demarcated by marginal parenchyma, medium-sized vestured intervessel pits, vessel-ray parenchyma pits similar in size and shape to intervessel pits, vasicentric to lozenge type aliform axial parenchyma, biseriate (70%) and uniseriate (30%) homocellular rays, non-septate and septate fibers, and long chains (10+) of prismatic crystals in chambered axial parenchyma cells. These features suggest a relationship with Peltophorum (Vogel) Benth. (Leguminosae: Caesalpinioideae). The vessel diameter and vessel density of the El Palmar woods are consistent with the temperate-warm, humid-semiarid climate inferred for this region during the late Pleistocene.

In: IAWA Journal

A new species of Pistacioxylon, Pistacioxylon leilaoensis Cheng et al., showing affinities with Pistacia of the Anacardiaceae is described from the Miocene of Leilao, Yuanmou Basin, Yunnan Province, southwest China. It provides data for reconstructing the phytogeographic history of Pistacia and the paleoenvironment of the Yuanmou Basin. This fossil suggests a long history of exchange of various taxa including Pistacia between Europe and East Asia during the Tertiary.

In: IAWA Journal

Numerous permineralized axes of Middle Triassic age from Fremouw Peak, Antarctica show evidence of mechanical wounding and wound responses. These consist of both elongate and triangular-shaped scars. Some scars can be detected beneath subsequent secondary xylem, indicating that wounding occurred early in stem development. In other stems, scars remained open suggesting late wounding and the permanent disruption of the cambium. In cross section most stems display little cal1ustissue, but wound periderm can be seen along the margin of the scar. In some stems the wound phellogen has formed phellem and phelloderm within the wounded area oriented perpendicular to the growth rings. Although some scars resemble those produced by fires, we were unable to document the presence of charcoal around scars. In modem ecosystems wounds may be caused by other agents, including debris drifting in floods, flowing ice, avalanche s, and animals . Each of these potential sources is reviewed in relationship to the paleoclimate in the region during the Triassic.

In: IAWA Journal

The wood anatomy of Metasequoia is similar to that of Glyptostrobus. Past descriptions of these woods have reported conflicting separation features. Using an increased sample size we have provided updated descriptions of these woods. We also review previously published criteria and discuss their validity. We introduce new characters (presence of ray cell separation and number of cells per square millimeter in transverse section of earlywood) and discuss the relative merit of these compared to previously described characters: arrangement of cross-field pits, features of the horizontal end walls of longitudinal parenchyma, transition from earlywood to latewood, abundance/distribution of longitudinal parenchyma, and aroma.

In: IAWA Journal

This paper documents the first record of permineralised wood from Middle Jurassic coal bearing deposits to the north of Kerman, Iran, deposited c. 170 million years before present. The coniferous woods have character combinations resembling, and thus have been assigned to, the genera Xenoxylon Gothan and Agathoxylon Hartig. Since Xenoxylon is essentially Laurasian and Agathoxylon has been recorded from the Northern Hemisphere during the Mesozoic, these woods help confirm conclusions from recent geological studies that place the Kerman Basin of Iran in southern Laurasia during the Jurassic.

In: IAWA Journal

Several anatomieally preserved twigs, a branehing speeimen and the wood of a large axis with affinities to Rosaeeae are deseribed from the Prineeton ehert (Middle Eoeene) of British Columbia, Canada. Speeimens are eharaeterised by a heteroeellular pith with a peri-medullary rone of thiek-walled oval eells and semi-ring-porous seeondary xylem with vertieal traumatie duets, fibres with eireular bordered pits, and mostly seanty paratracheal and oeeasionally apotracheal parenehyma. Ray to vessel pitting is similar to the alternate intervaseular pitting. Seeondary phloem is eomposed of tangentially oriented diseontinuous bands of alternating fibres and thinwalled eells. Seeondary eortical tissues are represented by a phelloderm eharaeterised by rectangular eells and phellern with rectangular eoneave eells. Anatomical variation between speeimens can be related to age of the woody axes. Juvenile and mature wood of this speeies differ in vessel arrangement and presenee of scanty paratracheal parenchyma in mature wood. Vessel elements are arranged in radial multiples, oeeasional clusters as well as solitary vessels. Tyloses and dark cellular contents are present mainly in mature wood. Some twigs have a heterocellular pith with a few scattered cells with dark contents or, occasionally, short irregular rows of these cells. In the branching specimen eells of this type also are organised in longer rows. Together, these anatomical features suggest that all specimens belong to the same taxon, Prunus allenbyensis Cevallos-Ferriz ' Stockey n. sp. Anatomy of this plant reinforces the interpretation of a subtropical to temperate climate during the time of deposition.

In: IAWA Journal

Newly collected fossil woods from the mid to late Oligocene of Thrace (the European part of Turkey) were identified as Sequoioxylon Torrey, thereby extending the known range of this conifer genus in space and time.

In: IAWA Journal

Two fossil wood species Celastrinoxylon celastroides and Ficoxylon cretaceum are reported and described for the first time from the Farafra Oasis in Egypt. They are compared to earlier descriptions of these species from Egypt and other parts of Africa.

In: IAWA Journal

Measuring density of silicified wood and determining weight loss after 450°C heating provides useful data for interpreting the process of permineralization. These simple gravimetric methods do not replace X-ray diffraction, electron microscopy, polarized light microscopy, Raman spectroscopy, and other specialized techniques for studying fossil wood, but they can be performed rapidly, and require minimal laboratory facilities. Woods mineralized with opal have densities of 1.9–2.1 g/cm3, compared to 2.3–2.6 g/cm3 for wood mineralized with chalcedony or quartz. Weight loss after 450°C heating, commonly described as “loss on ignition” can be used to roughly estimate the % of original organic matter that remains in chalcedony or quartz-mineralized wood, using the density of extant taxa for comparison. For opalized wood, 450°C weight loss mostly represents dehydration of the hydrous silica. Data from specimens from 20 localities reveal two characteristics: 1) silicified woods typically consist either of opal or chalcedony/quartz, not an intermediate mixture of the two silica polymorphs; 2) the percentage of organic matter that remains after petrifaction is usually very small.

In: IAWA Journal