Javelinoxylon,an Upper Cretaceous dicotyledonous tree from Big Bend National Park,Texas, with presumed malvalean affinities

Well-preserved petrified woods from the Maastrichtian of Big Bend National Park, Texas, with a combination of characters seen in the Malvales are described as Javelinoxylon multiporosum gen. et sp. nov. One log is over 70 cm in diameter and is riddled with termite galleries; this specimen provides additional documentation for the occurrence of dicotyledonous trees in the Late Cretaceous. These woods have structure different from any other known Cretaceous dicotyledonous wood and are advanced in the Baileyan sense as vessel elements are relatively short, perforations are exclusively simple, vessels are commonly in long radial multiples, and rays are storied. This is the earliest record for woods with storied structure. The occurrence of large dicotyledonous trees with advanced wood structure in Big Bend suggests there were differences between the Late Cretaceous vegetation of the northern Rocky Mountains and the Big Bend region.     

PALEOCENE DICOTYLEDONOUS TREES FROM BIG BEND NATIONAL PARK,TEXAS: VARIABILITY IN WOOD TYPES COMMON IN THE LATE CRETACEOUS AND EARLY TERTIARY,AND ECOLOGICAL INFERENCES

Paraphyllanthoxylon abbottii n. sp. and cf. Plataninium haydenii Felix from the Paleocene Black Peaks Formation, Big Bend National Park, Texas, are the first Paleocene dicotyledonous woods described from North America. Both represent wood types common in the Cretaceous. There are 30 logs of Paraphyllanthoxylon abbottii; it is rare that a single locality has such as large number of petrified dicotyledonous logs with a similar structural pattern, and the variability in mature wood structure can be documented. Paraphyllanthoxylon abbottii has a combination of features that occurs in many dicotyledonous families, but it is most similar to genera of Burseraceae. The Big Bend Paraphyllanthoxylon trees lack distinct growth rings, which suggests they grew in a climate without marked seasonality; they have high (10–74) vulnerability indices; such high values occur in extant tropical trees. The type species of Paraphyllanthoxylon, P. arizonense Bailey was reexamined, and its quantitative features are described. Aplectotremas Serlin of Albian age from the Edwards Limestone has anatomy like Paraphyllanthoxylon, and most probably is wood from a tree. The wood designated cf. Plataninium haydenii Felix resembles extant Platanaceae but differs in having exclusively scalariform perforation plates. Comparison of this wood with other platanoid woods suggests that in platanoid woods there has been a shortening of vessel elements and a decrease in the frequency of scalariform perforation plates from the Cretaceous through the Tertiary. These changes are consistent with the Baileyan model for specialization in tracheary elements.     

黑龙江晚白垩世化石木及其古环境研究

描述了3种出自黑龙江省嘉荫县晚自垩世的化石木:嘉荫柏型木(Cupressinoxylon jiayinense WangR.F.,Wang Y.F.et Chen Y.Z.)、柳杉型木(Taxodioxylon cryptomeria Schonfeld)和黑龙江原始云杉型木(Protopiceoxylon amurense DU N.Z.)。它们分别与现存的柏木属(Cupressus)、柳杉属(Cryptomeria)和油杉属(Keteleeria)有较近的亲缘关系。综合化石本研究与其现存近缘3属的地理分布区的环境分析和已有的植物叶大化石及孢粉的研究成果,黑龙江嘉荫地区晚自垩世的植被类型为针阔叶混交林,植物群由松柏类和阔叶树种组成,大多数是亚热带-暖温带分子,少量是温带分子。同时,嘉荫柏型木中真菌菌丝的侵入生长指示湿热生境的存在。上述证据表明黑龙江省嘉荫县晚自垩世为温暖、湿润的亚热带-暖温带气候。     

Fossil Woods from Late Cretaceous of Heilongjiang Province,Northeast China,and Their Palaeoenviromental Implications

Three species of fossil coniferous woods, Cupressinoxylon jiayinense Wang R. F., Wang Y. F. et Chen Y. Z., Taxodioxylon cryptomeria Schonfeld and Protopiceoxylon amurense Du N. Z. from late Cretaceous of Heilongjiang Province,Northeast China, were described. Their wood structural characters showed their affinities to the extant Cupressus, Cryptomeria and Keteleeria respectively. The data from fossil woods, fossil foliage and pollen assemblage of late Cretaceous in the same region showed that the flora consists of conifers and broad-leaved trees and most elements were subtropic or warm-temperate, only a few of them were temperate vegetation. At the same time, the occurrence of fungi filaments in the wood of Cupressinoxylon fiayinense might suggest a type of humid and warm environment. All of these evidences indicated that a humid warm temperate or subtropic paleoclimate had existed in Heilongjiang Province during Late Cretaceous.     

Fossil Ponderosa-like Pine Wood from the Upper Cretaceous of North-east Mississippi

Petrified wood from the Lower Upper Cretaceous of north-easternMississippi (Eutaw Formation) in thin-section is most similarto extant Pinus woods of section Pinus, subsection Ponderosae.However, several features also suggest woods of subsection Australes.Based on anatomical detail, geologic age and geographic position,this fossil may represent an ancestral connection between thetwo subsections. Pinuxylon eutawense, silicified wood, Cretaceous, Mississippi, Pinus ponderosa, Pinus taeda     

FLORA OF THE LOWER CRETACEOUS CEDAR MOUNTAIN FORMATION OF UTAH AND COLORADO. PART III: ICACINOXYLON PITTIENSE N. SP

Icacinoxylon pittiense, a new species of angiospermous wood from the Lower Cretaceous Cedar Mountain Formation of Utah is described and compared with similar fossil and modem woods. It is distinguished from other species of Icacinoxylon by its thick-walled fiber-tracheids with their walls making up at least 50% of the total diameter of the cells, conspicuous bordered pits with obliquely crossing extended apertures on both the tangential and radial walls of its fiber-tracheids, scalariform perforation plates with as few as four or greater than 30 bars, transitional opposite to scalariform pitting on its vessel walls, thick-walled ray cells, and distinct sheath or border cells in its rays. Icacinoxylon pittiense is the first species of this genus to be reported from Cretaceous sediments. This wood is of special interest because very few angiosperm woods have been reported from lower Cretaceous strata.     

Fossil wood Sequoioxylon dimyense sp. nov. (Cupressaceae) from the upper cretaceous of Zeya-Bureya basin, Russian Far East

A new species Sequoioxylon dimyense (Cupressaceae) is described from the Middle Maastrichtian (Upper Cretaceous) deposits of the Zeya-Bureya basin (Russian Far East) based on the fossil wood anatomy. The new species is characterized by combination of anatomical wood characters of the modern representatives of the subfamily Sequoioideae.     

Palaeoecology of the Miocene El Cien Formation (Mexico) as determined from wood anatomical characters

In order to establish the general environmental conditions under which the plants of the El Cien Formation grew during the Miocene, wood anatomical features from several extant ecological categories (southern California flora) and communities (Brazil, Mexico and Suriname) as well as those of the El Cien paleocommunity were analysed using different statistical approaches. We find a significant correlation between 42 characters of 199 species and 11 climate variables which suggests a close association of wood characters with temperature, whereas characters such as diameter, frequency, and grouping of vessels are more closely related to evaporation. The expression of various wood characters depends on more than one climate variable. There are no doubts regarding the tropical affiliation of the El Cien fossil flora but water availability and seasonality of the system are less clear. Principal component and cluster analyses of two different datasets (423 species, 9 characters and 223 species, 32 characters) suggest that the physiognomy of the fossil assemblage of El Cien was highly efficient in water transport, but also highly vulnerable to embolisms. Characters such as vessel diameter, frequency and grouping suggest proximity to a tropical rain forest, whereas the proportion of ring semi ring porous woods brings the El Cien paleoflora closer to forests with slightly xeromorphic physiognomy, probably a tropical deciduous or semi-deciduous forest. This condition is paralleled with the taxonomic composition of the El Cien fossil plants since their Nearest Living Relatives (NLR) can be referred to both humid or more (seasonally) dry environments. Derived regression analysis models suggest that the paleoflora prospered under conditions with an evaporation regime similar to that of the tropical rain forest.     

Prevalence of wood characters in eastern North America: what characters are most promising for interpreting climates from fossil wood?

The frequency of wood-anatomical characters in the eastern North America dicotyledonous tree flora shows spatial variance that can be related to climate (40% of the variation in 18 characters is explained by temperature and precipitation). Percent of taxa with rings varies with mean annual temperature, but the relationship is weak and the difficulties in making determinations as to presence or absence of rings make this character a problematic climatic indicator. Significant climate sensitivity is seen among characters pertaining to: a) vessel size and density (in diffuse-porous woods); 2) vessel arrangement; 3) parenchyma types; and 4) rays. Overall, the anatomical variables can be used to represent 82% of the variance in total precipitation and 91% of the variance in mean annual temperature within the study area. These results demonstrate the possibility of deriving a multivariate representation of the response of wood to climate that will be useful in climate reconstruction and comprise a source of information similar to that obtainable from leaf morphology and permitting estimates of precipitation as well as temperature.     

Mesozoic woods from India: Nomenclature review and palaeoclimatic implications

Nomenclature reappraisal, diversity pattern and palaeoclimatic implications of Jurassic, Triassic and Early Cretaceous pycnoxylic woods in India are undertaken in the present study. Among the fourteen generic names published previously, only eight are validly published and the rest are nomenclaturally illegitimate. About 51 species were reported under these genera to date. There is a gradual increase of species diversity of fossil wood from the Triassic to Early Cretaceous. The nature of the growth rings was applied to understand the palaeoclimate. The lack of distinct growth rings in the Triassic woods suggests absence of seasonality. The Jurassic woods with an inconsistency in growth rings and presence of growth interruptions suggest climate was seasonal and turbulent. During the Early Cretaceous, conifer dominated vegetation and with wider growth rings and gradual transition suggests warm environments with pronounced seasonality. The general increase in mean ring width from the Triassic to Early Cretaceous indicates ameliorating climatic conditions, particularly benign summer conditions.     

A new fossil flower from the Turonian of New Jersey: Dressiantha bicarpellata gen. et sp. nov. (Capparales)

Recent discoveries of fossil reproductive structures from deposits of the Raritan Formation in New Jersey (Turonian, Upper Cretaceous, ~90 million years BP) include a previously undescribed representative of the Order Capparales. The fossils are usually charcoalified with three-dimensional structure and excellent anatomical details. In the present contribution, we introduce a taxon represented by fossil flowers that have a combination of characters now found in the families of the Order Capparales sensu Cronquist. The fossil species is characterized by an unique suite of characters, such as the presence of a gynophore, arrangement of the sepals, unequal petal size, monothecal anthers, and a bicarpellate gynoecium, that are found in extant families of the Order Capparales. This new taxon constitutes an important addition to our understanding of Cretaceous angiosperm diversity and represents the oldest known fossil record for the Capparales. Heretofore, the oldest known capparalean was from the Late Tertiary sediments of North America.     

Ecological wood anatomy of NepaleseRhododendron (Ericaceae). 1. Interspecific variation

The relationship of selected wood anatomical characters of NepaleseRhododendron with stem diameter, plant height, altitude, and plant form was investigated. We studied one to three specimens each of 26 species: five species each of trees and subtrees I, three species of subtrees II, and 13 species of shrubs. Multiple regression analysis and actual distribution of character values show that pore characters and multiseriate ray ratio have a stronger correlation with stem diameter than altitude; that pore density, vessel element length, fiber-tracheid length, and multiseriate ray density and width are equally related to altitude and stem diameter, or to altitude and plant height; and that bar number, and multiseriate ray area and height have a stronger connection with altitude. Among the characters, average pore area is most strongly correlated with stem diameter and increases exponentially as diameter increases. For wood structure of NepaleseRhododendron, 17 to 63 % of the variation is affected by non-anatomical factors. The general trends in wood structure of NepaleseRhododendron show that trees and subtrees form one continuous unit whereas shrubs form another that often has wider ranges of variation.     

ANGIOSPERM WOOD FROM THE UPPER CRETACEOUS OF CENTRAL CALIFORNIA: PART II

Three species of fossil wood representing two genera are described. The specimens are from a collection of woods from the Upper Cretaceous Panoche formation of central California. Tetracentronites panochetris sp. nov. resembles angiosperm wood in ray structure and vascular pitting but lacks vessels. Plataninium platanoides sp. nov. is similar to the wood of Platanus, and the evidence presented points to a direct relationship. The resemblance between Plataninium cali-fornicum sp. nov. and the woods of certain Icacinaceae is discussed, but evidence of relationship is inconclusive.     

ANGIOSPERM WOOD FROM THE UPPER CRETACEOUS OF CENTRAL CALIFORNIA. III

Five species representing five genera are described. The specimens are part of a collection of woods from the Upper Cretaceous Panoche Formation of central California. Lardizabaloxylon cocculoides sp. n. resembles wood of those species of Cocculus of the Menispermaceae lacking included phloem. Carpinoxylon ostryopsoides sp. n. is similar to the wood of the Coryleae of the Betulaceae, particularly Ostryopsis. Riboidoxylon cretacea gen. et sp. n. is similar to the wood of Ilex of the Aquifoliaceae and also falls within the range of variation of the woods of the two closely related families, the Grossulariaceae and the Escalloniaceae. Mulleroxylon eupomalioides sp. n. falls well within the range of variation of the woods of the Magnoliaceae.     

Influence of environmental factors on the wood structure of living and fossil trees

The mechanism of wood development records in varying degree the effects of both external and internal factors that are operating at the time of development. As a result, fossil woods spanning the last 370 million years represent a unique palaeo-environmental data-store. Data concerning external factors that can be reclaimed consist of: presence or absence of growth rings; ring widths; relative proportions of earlywood and latewood and the nature of the transition between them; “false” and “frost” rings and evidence of damage by animals or fire; occurrence of reaction wood. These effects have to be seen against a background of the influences of the internal factors. The development of wood involves the action of plant growth regulators. The production of an entire season’s growth of wood depends on a supply of photosynthate, partly stored from the previous year, and the remainder directly from photosynthesis during the current one. In any population of trees of the same species there will be genetic variation which will lead to differences in the wood formed by the individual trees even if they have all grown in a largely similar environment. However the external factors exert a much greater influence than the internal ones. Our earliest fossil woods (Upper Devonian) show either seasonless growth patterns or, if weak rings are perceptible, then the increments are extensive. This is consistent with the palaeo-equatorial position of all recorded Devonian woods. In the Carboniferous a few sites (marginal in the tropical belt?) show subdued (weak) growth rings. By the time of the Gondwana glaciation strong rings are shown in high southern latitudes, but most surprisingly there are sizeable increments well inside the palaeoantarctic circle. This phenomenon persists into the Mesozoic where lack of growth rings shows consistency with positions within the palaeo-equatorial latitudes. However occurrence of Cretaceous high latitude wood growth demonstrates that given an adequate ambient temperature, forest growth was possible close to both poles. It is shown that this is consistent with the total energy flux known to occur now in high latitudes.     

Caryophyllales: a key group for understanding wood anatomy character states and their evolution

Definitions of character states in woods are softer than generally assumed, and more complex for workers to interpret. Only by a constant effort to transcend the limitations of glossaries can a more than partial understanding of wood anatomy and its evolution be achieved. The need for such an effort is most evident in a major group with sufficient wood diversity to demonstrate numerous problems in wood anatomical features. Caryophyllales s.l., with approximately 12 000 species, are such a group. Paradoxically, Caryophyllales offer many more interpretive problems than other ‘typically woody’ eudicot clades of comparable size: a wider range of wood structural patterns is represented in the order. An account of character expression diversity is presented for major wood characters of Caryophyllales. These characters include successive cambia (more extensively represented in Caryophyllales than elsewhere in angiosperms); vessel element perforation plates (non‐bordered and bordered, with and without constrictions); lateral wall pitting of vessels (notably pseudoscalariform patterns); vesturing and sculpturing on vessel walls; grouping of vessels; nature of tracheids and fibre‐tracheids, storying in libriform fibres, types of axial parenchyma, ray anatomy and shifts in ray ontogeny; juvenilism in rays; raylessness; occurrence of idioblasts; occurrence of a new cell type (ancistrocladan cells); correlations of raylessness with scattered bundle occurrence and other anatomical discoveries newly described and/or understood through the use of scanning electron microscopy and light microscopy. This study goes beyond summarizing or reportage and attempts interpretations in terms of shifts in degrees of juvenilism, diversification in habit, ecological occupancy strategies (with special attention to succulence) and phylogenetic change. Phylogenetic change in wood anatomy is held to be best interpreted when accompanied by an understanding of wood ontogeny, species ecology, species habit and taxonomic context. Wood anatomy of Caryophyllales demonstrates problems inherent in binary character definitions, mapping of morphological characters onto DNA‐based trees and attempts to analyse wood structure without taking into account ecological and habital features. The difficulties of bridging wood anatomy with physiology and ecology are briefly reviewed. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164 , 342–393.     

Lack of latitudinal trends in wood anatomy of Dodonaea viscosa (Sapindaceae), a species with a worldwide distribution

Latitudinal or altitudinal variation in several anatomical characters of wood is common for woody dicotyledonous genera with a wide distribution, but whether such variation exists at the species level is disputed. Latitudinal and altitudinal trends in wood anatomy of Dodonaea viscosa were studied, using 102 samples collected between 41.2° S and 33.3° N latitude and 7-2750 m altitude. We studied variation in four quantitative features: vessel element length, fiber length, vessel frequency, and tangential vessel diameter. Ontogenetic trends were minimal with a slight decrease or increase in the innermost stem and were negligible among the studied specimens. Throughout the distributional range of the species, no latitudinal trends were detected in either the Northern or Southern Hemispheres. Altitudinal trends were also nonexistent, except for two features in specimens from China and Japan. Absence of latitudinal or altitudinal trends in this widely distributed species suggests that in some species the species-level variation in wood anatomy is not controlled by ecological gradients.     

Effects of environmental factors on development of wood

This research tested the hypothesis that environmental factors (light, water, and nutrient levels) affect wood development. Specimens were placed in treatments of low, medium, or high levels of light, water, nitrogen, or phosphorus for one year. Control plants received medium levels of all factors, while experimental plants received medium levels of all factors except the experimental factor; for example, "high light" treatment consisted of high light but medium levels of water, nitrogen, and phosphorus. Some character changes seen in Cereus peruvianus were a reduction in mean vessel diameter and shoot elongation as a result of low nitrogen and low phosphorus treatments and a reduction in mean vessel density due to low light; high water induced broader vessels and greater shoot elongation. In Cereus tetragonus, low water treatment caused a reduction in mean vessel diameter, and high nitrogen decreased the amount of wood produced. Whereas all characters studied showed a significant correlation with at least one treatment in one species, few characters responded similarly between species. Estimated specific conductivity of wood could be altered by treatments affecting either vessel density or vessel diameter strongly or by treatments affecting both diameter and density weakly. Under the conditions tested, wood structure was stable but estimated conducting capacity was more flexible.     

云南中新世杉科化石木研究

利用光学显微镜和扫描电镜首次对云南省楚雄州晚中新世石灰坝组石鼓村层的钙化木材进行了解剖学研究.鉴定出两种类型的木材:柳杉型落羽杉型木(Taxodioxylon cryptomeripsoides Schonfeld)和杉木型落羽杉型木(Taxodioxylon cunninghamioides Watari).二者分别与现代柳杉属和杉木属具有最接近的亲缘关系.根据这两种杉科化石木现存最近亲缘种的生态环境,并综合其他资料,推测该地区在晚中新世为温暖湿润的亚热带气候环境.     

三种阔叶树雌雄异株木材结构的比较

在光学显微镜下较详细地比较了重阳木、大叶刺篱木和红毛丹,雌雄异株木材的结构。结果表明：同一种树木两性间木材结构总体上是很相似的,但有的定量特征差异显著甚至极显著。３个种的树木中,雌株木纤维壁腔比值较雄株的大,而分膈纤维和纤维管胞数量较小。雌株木材结构特点可能表明其木材具较强的机械支持能力,利用于果实的支持 。