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.
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.
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.
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.
Several specimens of Lauraceae fossil wood from the Cenozoic of Greece (southern part of Lesbos), the Czech Republic (Kadaň-Zadní Vrch Hill and Jáchymov), and Hungary (Ipolytarnóc) were studied. When considering whether they belonged to the speciose fossil wood genus Laurinoxylon, we reviewed the literature and data from InsideWood on fossil and modern woods. As a result, we propose criteria for excluding a fossil Lauraceae wood from Laurinoxylon and list the species that should be excluded from this genus. The criteria (filters) proposed to exclude a genus from having relationships with Laurinoxylon are: A. Axial parenchyma features: A1. Marginal axial parenchyma, A2. Aliform to aliform-confluent paratracheal parenchyma. B. Ray features: B1. Rays higher than 1 mm, B2. Exclusively homocellular rays, B3. Rays more than 5 cells wide, B4. Rays storied. C. Porosity features: Ring-porous. D. Idioblasts: Absence of idioblasts. Based on the distribution of idioblasts, we recognize four groups in Laurinoxylon (Type 1 - with idioblasts associated only with ray parenchyma cells, Type 2a - with idioblasts associated with both ray and axial parenchyma, Type 2b - with idioblasts associated both with rays and present among the fibres, and Type 3 - with idioblasts associated with ray and axial parenchyma and also among the fibres) and list the extant genera with features of those groups. Such grouping helps with interpreting the relationships of fossil lauraceous woods with extant genera. We discuss the Oligocene–Miocene European species that belong to these Laurinoxylon groups, noting that some warrant reassignment to different genera or even families. Future studies are needed to determine whether new genera should be established to accommodate these species. We propose the new combination Cinnamomoxylon variabile (Privé-Gill & Pelletier) Mantzouka, Karakitsios, Sakala & Wheeler.
Fossil woods from the El Cien Formation have yielded important information on the taxonomic composition and climate of a flora established in the west coast of Mexico during the Miocene. This report of a new genus and species, Ruprechtioxylon multiseptatus Cevallos-Ferriz, Martínez Cabrera et Calvillo-Canadell, is based on woods with the following combination of features: vessels solitary and in radial multiples of 2–3; vestured, alternate, oval to polygonal intervessel pits; vessel-ray and vessel-parenchyma pits similar in size to intervessel pits, but with slightly reduced to reduced borders; 2–5 septa per fibre; scanty paratracheal, unilateral and vasicentric axial parenchyma; uniseriate homocellular rays, occasionally locally biseriate; crystals in fibres. The presence of Ruprechtioxylon (Polygonaceae) in the El Cien Formation confirms that plants of lineages growing today under contrasting climates lived together in the past. This record adds a new species to the growing list of Neotropical taxa that were present in Mexico prior to the great Plio-Pleistocene exchange of biota in the Americas.
Fascination with petrified wood has stimulated interest in understanding the process of natural petrifaction. Early attempts of modeling natural petrifaction in the laboratory have been limited to mimicking incipient permineralization resulting in the creation of silica casts of pore spaces and inner cell walls. Silica lithomorphs produced through artificial silicification provided a possible avenue for studying microstructure of wood. More recently artificial petrifaction is motivated by the goal of creating advanced ceramic materials for engineering applications. The concept of using wood as a biotemplate has led to the creation of porous ceramics by cell wall replacement. To some extent artificial and natural petrifaction processes are comparable; although, some of the materials and procedures used in the laboratory are not found in nature. Research focused on the composition and structure of fossil wood from different-aged deposits is compared with research focused on the development of wood-templated porous ceramics. Differences and similarities in the pathways of natural silicification and creation of biomorphous ceramics are discussed. The comparison between artificial and natural silicification highlights the particular significance of the degree to which (de)lignification is needed for silica permeation.
Fossil root- and stemwood of Chionanthus retusus has been found from the Late Pleistocene stratum at Akashi, Hyogo Prefecture, central Japan. The woods of fossil and extant C. retusus are described and compared. The fossil rootwood closely resembles that of the extant individuals in being ring-porous with large pores arranged in one layer in the earlywood, and small pores that gradually decrease in diameter from the earlywood, and are arranged in a flame-like pattern in the latewood. It differs from the wood of the extant species in the larger diameter of wide pores, the quite gradual decrease in vessel diameter from the earlywood to the latewood, and the narrower and lower rays. The fossil stemwood is quite similar to the stemwood of extant C. retusus in being ring-porous with large pores arranged in one or two layers in the earlywood, and small pores .that abruptly decrease in diameter from the earlywood, and are arranged in a flame-like pattern. It differs from the wood of the extant species in the larger diameter of wide pores, and the lower rays. Based on their similarity, these fossil woods are identified as the rootand stemwood of C. retusus.