We describe a new fossil wood from the San Carlos Formation (Coniacian- Maastrichtian) in Chihuahua, northern Mexico. This Malvaceae s.l. wood is diffuse porous, vessels are solitary and in radial multiples, simple perforation plates, small alternate intervessel pits, vessel-ray parenchyma pits that are rounded with reduced borders, septate and nonseptate fibers, homocellular and heterocellular rays, and storied rays and vessel elements. These features support its inclusion within the genus Javelinoxylon, Malvaceae s.l., which occurs in other Upper Cretaceous localities in northern Mexico (Olmos Formation) and Texas (Aguja and Javelina Formations). This San Carlos fossil wood is the earliest occurrence of storied structure in the fossil record and the earliest angiosperm record for the State of Chihuahua, Mexico.
Wood from an in situ permineralized forest from the Middle Triassic of Gordon Valley (Queen Alexandra Range, central Transantarctic Mountains) in Antarctica is described as a new taxon, Approximately 100 trunks in growth position are present at the site; they range from 13-61 cm in diameter and suggest that some of the trees were up to 20 m tall, Pits in the radial walls of the tracheids are of the abietinean type, Rays are uniseriate and 1-9 cells high; cross fields include one to two pits that appear to be simple, Axial parenchyma is absent. Pith and cortex are not preserved. The Antarctic wood is compared with existing fossil wood types from Antarctica and other parts of Gondwana. Although the fossil wood shares a number of characteristics with the Podocarpaceae, it differs from any existing genera and is described as a new taxon, Jeffersonioxylon gordonense.
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.
A gymnosperm wood is described from the Oligocene-Miocene of Hainan Island, South China. It is characterized by circular, thin-walled tracheids with resin plugs, 1–3-seriate alternate or opposite intertracheary pits in radial walls, 1–2-seriate rays, cross fields with 3–14 araucarioid cross-ﬁeld pits. These are features found in the Araucariaceae and the fossil is designated as Agathoxylon sp. Fossil woods with anatomical characteristics seen in the Araucariaceae are extremely rare in the North Hemisphere after the K/T boundary. Thus, this Agathoxylon from the Oligocene-Miocene of South China has significance for biogeographic studies.
One of the key functions of wood is hydraulic conductivity, and the general physical properties controlling this are well characterized in living plants. Modern species capture only a fraction of the known diversity of wood, which is well preserved in a fossil record that extends back over 400 million years to the origin of the vascular plants. Early fossil woods are known to differ in many key respects from woods of modern gymnosperms (e.g., tracheid size, secondary wall thickenings, lignin chemistry, cambium development) and recent discoveries are shedding new light on the earliest stages of wood evolution, raising questions about the performance of these systems and their functions. We provide an overview of the early fossil record focusing on tracheid morphology in the earliest primary and secondary xylem and on cambial development. The fossil record clearly shows that wood evolved in small stature plants prior to the evolution of a distinctive leaf-stem-root organography. The hydraulic properties of fossil woods cannot be measured directly, but with the development of mathematical models it is becoming increasingly feasible to make inferences and quantify performance, enabling comparison with modern woods. Perhaps the most difficult aspect of hydraulic conductance to quantify is the resistance of pits and other highly distinctive and unique secondary wall features in the earliest tracheids. New analytical methods, in particular X-ray synchrotron microtomography (PPC-SRμCT), open up the possibility of creating dynamic, three-dimensional models of permineralized woods facilitating the analysis of hydraulic and biomechanical properties.
of the Envigne valley (Vienne, Western France) 530 Woodcock DW, Meyer HW, Prado Y. 2019. The Piedra Chamana fossilwoods (Eocene, Peru), II 551 Pujana RR, Ruiz DP. 2019. Fossilwoods from the Eocene–Oligocene (Río Turbio Formation) of southwestern Patagonia (Santa Cruz province, Argentina) 596 Vanner
Inside Wood is an Internet-accessible wood anatomy reference, research, and teaching tool. The InsideWood database has coded wood anatomical descriptions based on the IAWA List of Microscopic Features for Hardwood Identification and is accompanied by a collection of photomicrographs. As of November 2010 there were over 5,800 descriptions and 36,000 images of modern woods, and over 1,600 descriptions and 2,000 images of fossil woods. CITES-listed timber species and other endangered woody plants are included in this digital collection hosted by North Carolina State University’s library. This web site has value in helping with wood identification because it has a multiple entry key that allows searching by presence or absence of IAWA features and it serves as a virtual reference collection whereby descriptions and images can be retrieved by searching by scientific or common name or other keywords.
Although araucarioid wood is poor in diagnostic characters, well in excess of 200 Late Paleozoic species have been described. This study presents a largescale anatomical analysis of this wood type based on the fossil wood collections from the Early Permian Mengkarang Formation of Sumatra, Indonesia. Principal Component Analysis visualisation, in conjunction with uni- and multivariate statistical analyses clearly show the wood from the Mengkarang Formation to be a contiguous micromorphological unit in which no individual species can be distinguished. Pycnoxylic wood species described previously from this collection or other collections from the Mengkarang Formation fall within the larger variability described here. Based on comparison with wood from modern-day Araucariaceae, the Early Permian specimens can be differentiated from extant (but unrelated) “araucarioids” by a few (continuous) characters.
The wood of Oleoxylon deccanense, reported informally in 1981 from the Deccan Intertrappean Beds of central India, is re-examined. We provide a formal diagnosis for the species and a more detailed description. The similarity to wood from species groups of the modern genera Chionanthus and Olea leads us to infer that this fossil taxon probably belongs to the monophyletic drupaceous subtribe Oleinae of the olive family, Oleaceae (Lamiales), although affinities with Rhamnaceae and Rutaceae cannot be wholly excluded. Since the fossil is from a late Maastrichtian-Danian horizon (65–67 MY BP) this would imply that a member of the Oleaceae was part of the flora that inhabited India several million years prior to the tectonic impact of India with Asia. The seemingly modern appearance of this and other Deccan fossil woods is briefly discussed.
Wood anatomy of Craigia W.W. Sm. & W.E. Evans (Malvaceae s.l.), a tree endemic to China and Vietnam, is described in order to provide new characters for assessing its affinities relative to other malvalean genera. Craigia has very low-density wood, with abundant diffuse-in-aggregate axial parenchyma and tile cells of the Pterospermum type in the multiseriate rays. Although Craigia is distinct from Tilia by the presence of tile cells, they share the feature of helically thickened vessels – supportive of the sister group status suggested for these two genera by other morphological characters and preliminary molecular data. Although Craigia is well represented in the fossil record based on fruits, we were unable to locate fossil woods corresponding in anatomy to that of the extant genus.