A New Species of Araucarioxylon Kraus from the Early Early Permian,Nei Mongol,China

A kind of silicified fossil wood with mixed pits on the radial tracheid wall is described. The fossil wood was collected from the top of Taiyuan Formation (early Early Permian) in Wuda Mining District, Nei Mongol. Compared with the Paleozoic fossil woods in the world, it is put into Araucarioxylon Kraus and named as A. laoshidanense sp. nov. Based on the character of possessing mixed pittings (alternate and opposite pittings) on the radial tracheid wall, the fossil wood is believed to be one of the unknown primitive conifers.Diagnosis of the new species: Only secondary xylem preserved and consisting of axial tracheids and rays. Growth ring boundary, resin duct and axial parenchyma absent. One to Four (commonly 2or3) seriates of bordered pits mostly alternate but sometimes opposite）on the radial tracheid wall. One to Four (commonly1, rarely2 to 4) Cupressoid pits in each cross-field. Rays usually uniseriate, sometimes partly-biseriate and 2 to 39 (mainly3-5) cells high.     

A Method To Distinguish Between Woods Produced By Evergreen And Deciduous Coniferopsids On The Basis Of Growth Ring Anatomy: A New Palaeoecological Tool

A method is outlined in which woods produced by deciduous and evergreen coniferopsids may be distinguished from one another on the basis of a quantitative analysis of growth ring anatomy. In this method the diameter of successive tracheid cells was measured across growth rings in modern coniferopsid woods, viewed using standard transverse anatomical sections. The cumulative algebraic sum of each cell's deviation from the mean was then calculated for each growth ring increment and plotted as a zero-trending curve (CSDM curve). Deciduous conifer and ginkgo species dominantly possess symmetrical or left-skewed CSDM curves whilst evergreen conifer species dominantly possess right-skewed CSDM curves. These data suggest that in most cases it may be possible to distinguish between evergreen and deciduous fossil coniferopsid species using wood anatomical characteristics, thus providing important insight into coniferopsid palaeoecology. key words : growth rings, conifer wood, palaeoclimate, evergreen, deciduous.     

Charred wood of Prototaxoxylon from the Wuchiapingian Wutonggou Formation (Permian) of Dalongkou,northern Bogda Mountains,northwestern China

Charred wood occurs sporadically in sedimentary rocks in China. A marcroscopic charcoal with well-preserved anatomical structure is described from the Wuchiapiangian Wutonggou Formation in the southern part of Dalongkou section, northern Bogda Mountains in the Junggar Basin, northwestern China. It is characterized by uniseriate radial tracheidal pitting, taxaceous tertiary spiral thickenings in the tracheidal walls, uniseriate tangential tracheidal pitting, homogeneous, uniseriate, 2–10 cells high xylem rays, and 1–2 pits in each cross-field. It is assigned to Prototaxoxylon uniseriale Prasad. The uniseriate, bordered, contiguous, rarely separate tangential pitting of P. uniseriale is evidenced clearly for the first time. The features of this species show a close affinity with conifers. The coniferous charred wood may have been derived from an extrabasinal forest, perhaps from upland environment deep within the hinterland, according to results of modern taphonomic research.     

Fossil Woods From Williams Point Beds, Livingston Island, Antarctica: A Late Cretaceous Southern High Latitude Flora

The wood flora from Williams Point, Livingston Island, contains 12 wood types of gymnosperm and angiosperm origin. Recent collections of material have increased the biodiversity of a postulated species-rich vegetation. The gymnosperm wood can be readily assigned to four form-genera: Araucarioxylon Kraus, Araucariopitys Jeffrey, Podocarpoxylon Gothan and Sahnioxylon Bose and Sah. This indicates a diversity of coniferous araucarian and podocarp trees alongside woods of uncertain affinity ( Sahnioxylon ; Bennettitales). Two angiosperm morphotypes are assigned to the organ genera Hedycaryoxylon Su¨ss (Monimiaceae) and Weinmannioxylon Petriella (Cunoniaceae). The remaining four taxa of angiosperm wood cannot be confidently placed in extant families as they exhibit features that suggest relationships with the Magnoliidae, Hamamelidae and Rosidae. This paper presents the first comprehensive taxonomic revision of the wood flora from Livingston Island and discusses the palaeoecology that prevailed at a latitude of about 60 degrees south during the Late Cretaceous. Newly described taxa are Araucarioxylon chapmanae sp. nov., Araucariopitys antarcticus sp. nov., Podocarpoxylon chapmanae sp. nov., P. verticalis sp. nov., P. communis sp. nov., Weinmannioxylon ackamoides sp. nov., Antarctoxylon livingstonensis gen. et sp. nov., A. multiseriatum gen. et sp. nov., A. heteroporosum gen. et sp. nov. and A. uniperforatum gen et sp. nov.     

内蒙古早二叠世早期南洋杉型木属一新种

报道了一种具混合型纹孔（互列式纹孔和对列式纹孔）的化石本。化石木产自内蒙古乌达矿区老石旦矿附近太原组上部,地质时代为早二叠世早期。经比较,确认为南洋杉型木属（Ａｒａｕｃａｒｉｏｘｙｌｏｎ Ｋｒａｕｓ）一种新;老石旦南洋杉型木（Ａｒａｕｃａｒｉｏｘｙｌｏｎ ｌａｏｓｈｉｄａｎｅｎｓｅ ｓｐ．ｎｏｖ．）．根据混合型纹孔的存在及其他特征,认为新种可能代表了一种原始的松杉类植物的木材化石。主要特征：仅保存     

New records of Early Cretaceous petrified wood in Yumen,northwestern Gansu Province,China and their palaeoclimatic implications

Several fossil woods from Early Cretaceous sediments in Yumen City in northwestern North China Block, China, have been described. They belong to two fossil wood taxa, Piceoxylon yumeniense Zhou, Peng, Deng, Zhang and Yang n. sp. and Protophyllocladoxylon chijinense Zhou, Peng, Deng, Zhang and Yang n. sp. The well-preserved specimens yield secondary xylem with distinct growth rings. Piceoxylon yumeniense exhibits cross-field with taxodioid pits as well as two distinct xylem ray types. The bi- to triseriate rays are characterised by one or two horizontal resin canals with unequal uniseriate ends. Protophyllocladoxylon chijinense Zhou, Peng, Deng, Zhang and Yang n. sp. shows window-like cross-field pits, which are occasionally cupressoid and have uniseriate xylem rays. These fossil wood records improve our understanding of the fossil diversity, floral composition and palaeoclimate of the Xiagou Formation. Palaeoclimatic analysis of the palaeoxylogical assemblage indicates that the northwestern Gansu region predominantly exhibited a warm and wet climate condition, while a brief cooling event may have occurred in the region during the Early Cretaceous.     

Two Fossil Woods from Heilongjiang Sheng of China

Two fossil coniferous woods, Xenoxylon latiporosum (Cramer) Gothan and Protopiceoxylon amurense sp. nov. found in Heilongjiang Sheng of China are described in this paper. The diagnosis of Protopiceoxylon amurense sp. nov. is as follows: Growth rings distinct. The transition from the early wood to the late wood slightly abrupt. Tracheids of the early wood square to rectangular in the transverse section. Bordered pits on the radial walls of early wood traeheids 1-2-seriate, opposite, circular with round apertures. The erassula well marked. Walls of the late wood traeheids much thickened. Rays uniseriate and partly biseriate, 1–45 cells high. The highness of the biseriate part is often more than 2/3 that of the ray. Transverse walls of ray cells rather densely pitted and the tangential walls with marked nodular thickenings. The pitting of the cross-field is small, simple or taxodioid type. The axial wood parenchyma absent. The axial resin canal, both traumatic and normal, present, separate or gathered in tangential rows. Epithelial cells with thickwalls are more than 10 in number. The affinities of the two woods are discussed. The age of the fossil woods is assigned to Late Jurassic to Early Cretaceous. It is inferred that they grew in the then north subtropical warm temperate zone and on a hilly area with an elevation of 1000 metres approximately.     

Sclerospiroxylon xinjiangensis nov. sp., a gymnospermous wood from the Kungurian (lower Permian) southern Bogda Mountains,northwestern China: Systematics and palaeoecology

A new silicified wood, Sclerospiroxylon xinjiangensis Wan, Yang et Wang nov. sp., is described from the Cisuralian (lower Permian) Hongyanchi Formation in southeast Tarlong section, Turpan City, Xinjiang Uygur Autonomous Region, northwestern China. The fossil wood is composed of pith, primary xylem and Prototaxoxylon-type secondary xylem. The pith is solid, circular, heterocellular, with sclerenchyma and parenchyma. The primary xylem is endarch to mesarch, with scalariform thickenings on tracheid walls. The secondary xylem is pycnoxylic, composed of tracheids and parenchymatous rays. Growth rings are distinct. Tracheids have mostly uniseriate, partially biseriate araucarian pitting on their radial walls. Helical thickenings are always present on both the radial and the tangential walls. Rays are 2–14 cells high, with smooth walls. There are 2 to 7, commonly 2 to 4 cupressoid pits in each cross-field. Leaf traces suggest that S. xinjiangensis nov. sp. was evergreen with a leaf retention time of at least 15 years. Based on the sedimentological evidence, growth rings within the S. xinjiangensis nov. sp. could have been caused by seasonal climatic variations, with unfavorable seasons of drought or low temperature. Low percentage of latewood in each growth ring is probably due to the intensity of climatic seasonality and/or long leaf longevity.     

Fossil wood of Eristophyton sp. from the Carboniferous deposits of northern Russia (Arkhangelsk region)

Permineralised wood of Eristophyton sp. is first described from the Carboniferous deposits of the Arkhangelsk region, northern Russia. The specimens used in the study show scalariform thickening of the metaxylem tracheids both on radial and tangential walls. Eristophyton sp. indicates well preserved elements of secondary xylem: uni-, rarely biseriate xylem rays up to 15–16 cells high; uni-, multiseriate tracheid pitting only on radial walls; 1–8 contiguous cross-field pits and their inclined narrow apertures. A brief review and comparison with known anatomically preserved plants from the Lower Carboniferous of different localities of Scotland, France, USA and Poland is discussed.     

Illicioxylon, an Element of Gondwanan Polar Forests? Late Cretaceous and Early Tertiary Woods of Antarctica

The Late Cretaceous and early Tertiary sediments from the northernPeninsula region of Antarctica yield a rich assemblage of fossilwood with well preserved anatomy. Wood specimens of a previouslyrecognized morphotype are described. The woods are characterizedby diffuse porous wood, mainly solitary vessels with long scalariformperforation plates, scalariform and opposite vessel-ray pitting,generally uniseriate and biseriate heterogeneous rays, and tracheidswith obvious uniseriate, circulate, bordered pits. These fossilspecimens show greatest anatomical similarity to the organ genusIllicioxylon Gottwald and extant members of the Illiciaceae.The occurrence of illiciaceous-like wood in Gondwana suggeststhat the distribution of this family may have been more widespreadin the geological past and that a relatively warm temperateclimate prevailed over the northern Peninsula region of Antarcticaduring the Late Cretaceous and early Cenozoic. Copyright 2000Annals of Botany Company Fossil, wood, Illiciaceae, Illicioxylon, Illicium, Cretaceous, Tertiary, Gondwana, Antarctica     

CALLIXYLON FROM THE UPPER DEVONIAN OF NORTHWESTERN ALBERTA

Campbell, J. D. (Res. Council Alberta, Edmonton.) Callixylon from the Upper Devonian of northwestern Alberta. Amer. Jour. Bot. 50(7): 648–652. Illus. 1963.—An oil-well core from the “Granite Wash” of probable early Late Devonian age (Wood bend equivalent) in the Peace River region of northwestern Alberta yielded a thin pyritized chip of coniferoid wood. The pith is not represented, but the secondary tracheid pitting, exhibiting radially aligned clusters of 5–10 araucarioid pits, indicates that the specimen is referable to the wood-type usually called Callixylon, now believed to be the axis of the leaf-genus Archaeopleris. In its low and regularly uniseriate or rarely biseriate rays, with no apparent ray tracheids, the specimen may resemble the species Callixylon trifdievi Zalessky (1909) from the Upper Devonian of Russia, and thus lend some small support to the postulation of a Late Devonian land connection between northwestern North America and Europe.     

Ginkgoalean woods from the Jurassic of Argentina: Taxonomic considerations and palaeogeographical distribution

A specimen of Baieroxylon rocablanquense nov. sp. from the Roca Blanca Formation (Early Jurassic), and a specimen of Ginkgomyeloxylon tanzanii Giraud and Hankel from the La Matilde Formation (Middle Jurassic), both located in the Santa Cruz province, Argentina, are described in detail. Identification of the morphogenus Baieroxylon is based upon secondary xylem characteristics (cross-field tracheid pitting, cross-fields and ray characters), while identification of Ginkgomyeloxylon is based upon pith, primary xylem and secondary xylem features. A synthesis of Ginkgoalean woods is presented, which combines diagnostic anatomical evidence with data related to stratigraphic and paleogeographical distributions. Based on the results of this analysis, a key for genus-level identification is provided and a new genus, Ginkgopitys, is proposed. These results are used to elucidate global patterns of historical distribution over the course of geological time. In Gondwana, a great diversity of “mixed-type” woods was present during the Mesozoic, especially during the Late Triassic. In contrast, in Laurasia a lower diversity of the mixed-type is recorded for the Paleozoic and Mesozoic, with increases in “abietinoid-type” wood – similar to extant Ginkgo – taking place at the beginning of the Cretaceous. During the Jurassic and Early Cretaceous in both Laurasia and Gondwana, mixed-type and abietinoid-type woods co-existed, illustrating that important evolutionary changes in wood anatomy occurred during the Mesozoic (Jurassic-Cretaceous).     

Palaeocupressinoxylon uniseriale n. gen. n. sp., a gymnospermous wood from the upper Permian of Central Taodonggou,southern Bogda Mountains,northwestern China

A silicified wood, Palaeocupressinoxylon uniseriale n. gen. n. sp., is described from the upper Permian of the Central Taodonggou section, Turpan–Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China. Multidisciplinary data including U–Pb ID–TIMS zircon dating, vertebrate and invertebrate biostratigraphic, and cyclostratigraphic correlation from current and previous studies indicate that the fossil bearing interval is Wuchiapingian (late Permian) in age. The pycnoxylic wood consists of thick-walled tracheids and parenchymatous rays. It is characterized by separated uniseriate radial tracheidal pits, uniseriate ray cells, and cupressoid cross-field pitting. The absence of growth rings in the wood, together with the occurrence of Argillisols, Gleysols, and Histosols above and below the fossil interval, suggests that a stable landscape and a perennially humid climate prevailed in the Taodonggou area during the Wuchiapingian.     

Inter-tracheid pitting and the hydraulic efficiency of conifer wood: the role of tracheid allometry and cavitation protection

Plant xylem must balance efficient delivery of water to the canopy against protection from air entry into the conduits via air-seeding. We investigated the relationship between tracheid allometry, end wall pitting, safety from air-seeding, and the hydraulic efficiency of conifer wood in order to better understand the trade-offs between effective transport and protection against air entry. Root and stem wood were sampled from conifers belonging to the Pinaceae, Cupressaceae, Podocarpaceae, and Araucariaceae. Hydraulic resistivity of tracheids decreased with increasing tracheid diameter and width, with 64 ± 4% residing in the end wall pitting regardless of tracheid size or phylogenetic affinity. This end-wall percentage was consistent with a near-optimal scaling between tracheid diameter and length that minimized flow resistance for a given tracheid length. There was no evidence that tracheid size and hydraulic efficiency were constrained by the role of the pits in protecting against cavitation by air-seeding. An increase in pit area resistance with safety from cavitation was observed only for species of the northern hemisphere (Pinaceae and Cupressaceae), but this variable was independent of tracheid size, and the increase in pit resistance did not significantly influence tracheid resistance. In contrast to recent work on angiosperm vessels, protection against air-seeding in conifer tracheids appears to be uncoupled from conduit size and conducting efficiency.     

辽西义县下白垩统沙海组木化石新材料

辽西地区下白垩统沙海组是我国北方地区重要的白垩纪木化石产出层位,其产出的木化石数量丰富、类型多样.尽管前人开展了部分研究,但目前对沙海组木化石植物群组成特征的认识仍相对薄弱.本文报道了辽西义县上石洞沟地区沙海组产出的木化石新材料,共鉴定出2属3种,分别为:Phyllocladoxylon cf.eboracense(H...     

TRACHEID BAR AND VESTURED PITS IN LEGUME SEEDS (LEGUMINOSAE: PAPILIONOIDEAE)

The tracheid bar, a strip composed of vertically oriented large tracheid-like cells (tracheoids), occurs only in the hilum of seeds of papilionoid legumes. An anatomical survey of the bar was made from seeds representing 232 species of 97 genera from 29 of the 31 tribes recognized by Polhill. Seeds were sectioned freehand, coated, then viewed by SEM. The tracheid bar is quite uniform in its general features throughout the subfamily, although differences in size and shape of both the bar and the tracheoids were found. Eight species from tribes considered to be among the primitive elements of the subfamily exhibited three variant forms: horizontal tracheary elements instead of the usual bar (2 species), tracheid bar with subtending but separate vascular bundle (1 species), and the tracheid bar with fused horizontal tracheary elements (5 species). Bordered pits of individual cells in the tracheid bar virtually always lacked a membrane and had smooth, warty, or variously elaborate vestures on the border. This appears to be the first report of vestured pits other than in secondary xylem. With some exceptions, bordered pits tended to be vestured in primitive tribes, warty in intermediate tribes, and smooth or only slightly warty in the most advanced tribes.     

四合木属四合木(蒺藜科)的木材解剖学研究

在光学显微镜和扫描电子显微镜下观察了蒺藜科四合木属四合木(Tetraena mongolica Maim.)木材结构.其导管分子直径小,管壁厚,分布密度高,分子短,端壁几乎水平,具单穿孔;管间纹孔为对列或互列的具缘纹孔;韧性纤维短、壁厚、壁上有较少的单纹孔;同型单列射线、分布密度高;轴向薄壁组织散生或傍导管生.这些表明四合木的木材解剖特征是与干旱环境条件是相适应的.     

Glutoxylon Chowdhury (Anacardiaceae): the first record of fossil wood from Bangladesh

This paper documents the first record of silicified fossil wood from a previously undescribed wood-rich horizon in the Sitakund Anticline, Eastern Bangladesh. The outcrop is composed of cross-stratified, fine-medium grained sandstones with bidirectional cross stratification indicative of a tidal environment, deposited ca. 5-5.2 million years before present (Miocene/Pliocene). The wood is characterised by large solitary vessels with alternate intervascular pits, banded parenchyma, uniseriate rays, and multiseriate rays with one radial canal per ray. This character combination closely resembles the wood of extant Gluta L. of the Anacardiaceae. This specimen has been assigned to the organ genus Glutoxylon Chowdhury erected for fossil woods with anatomical similarity to Gluta (including Melanorrhoea Wall.). The excellent preservation of this mature wood specimen illustrates the potential for using fossil wood from the Sitakund locality for palaeoecological studies in terms of biodiversity and adaptational response to climate change. Moreover such investigations of fossil woods from Bangladesh will compliment studies undertaken on fossil plants in other parts of Central and Southeastern Asia which will further the understanding of plant migration routes between India and Southeast Asia during the Tertiary.     

内蒙古霍林河煤田罗汉松科几种丝炭化木化石的研究

对采自内蒙古霍林河煤田霍林河组下含煤段的丝炭化木化石进行了扫描电镜观察和描述。经鉴定属于Ｐｏｄｏｃａｒｐｏｘｙｌｏｎ ｄａｃｒｙｄｉｏｉｄｅｓ ｓｐ．ｎｏｖ。、Ｐｏｄｏｃａｒｐｏｘｙｌｏｎ ｓｐ．、Ｐｈｙｌｌｏｃｌａｄｏｘｙｌｏｎ ｓｐ．１和Ｐｈｌｌｏｃｌａｄｏｘｙｌｏｎ ｓｐ．２。Ｐｏｄｏｃａｒｐｏｘｙｌｏｎ和Ｐｈｙｌｌｏｃｌａｄｏｘｙｌｏｎ是罗汉松科的两种古老的木材类型。