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1.
Wood samples of 49 specimens representing 31 species and 11 genera of woody balsaminoids, i.e., Balsaminaceae, Marcgraviaceae, Pellicieraceae, and Tetrameristaceae, were investigated using light microscopy and scanning electron microscopy. The wood structure of Marcgraviaceae, Pellicieraceae, and Tetrameristaceae is characterized by radial vessel multiples with simple perforation plates, alternate vessel pitting, apotracheal and paratracheal parenchyma, septate libriform fibers, and the presence of raphides in ray cells. Tetrameristaceae and Pellicieraceae are found to be closely related based on the occurrence of unilaterally compound vessel-ray pitting and multiseriate rays with long uniseriate ends. The narrow rays in Pelliciera are characteristic of this genus, but a broader concept of Tetrameristaceae including Pelliciera is favored. Within Marcgraviaceae, wide rays (more than five-seriate) are typical of the genus Marcgravia. Furthermore, there is evidence that the impact of altitude and habit plays an important role in the wood structure of this family. The wood structure of Balsaminaceae cannot be compared systematically with other balsaminoids because of their secondary woodiness. Balsaminaceae wood strongly differs due to the presence of exclusively upright ray cells in Impatiens niamniamensis, the absence of rays in Impatiens arguta, and the occurrence of several additional paedomorphic features in both species.  相似文献   

2.
Small diameter pyritized axes, commonly referred to as 'twigs', of fossil vitaceous and menispermaceous wood from the Lower Eocene, London Clay Formation of south-east England are described here for the first time. The vitaceous twigs, which represent the earliest known occurrence of fossil Vitaceae wood, are characterized by large diameter, solitary vessels, tall wide rays which dilate in the phloem region, scalariform intervessel pits and simple perforation plates. The wood anatomy supports a close relationship to the Vitaceae and in particular the genus Rhoicissus Planch. The menispermaceous twigs are characterized by medium to moderately large vessels, simple perforation plates, alternate intervascular pitting and very broad and high rays. The anatomical characters support a close relationship to the Menispermaceae and in particular the genera Tinomiscium Miers and Coscinium Colebr. However, as these fossil twigs are not exactly similar to any particular genus they have been placed in the organ genus, Vitacexoylon Wheeler and LaPasha and Menispermoxylon Vozenin-Serra, Privé-Gill & Ginsburg, with which, respectively, they have the greatest similarity. These specimens were studied using reflected light- and scanning electron microscopy.  相似文献   

3.
Austrovideira dettmannaegen. & sp. nov. from the early Oligocene Capella Flora in central Queensland is the first fossil Vitaceae wood described from the Southern Hemisphere. A new combination, Stafylioxylon ramunculiformis (Poole & Wilkinson) Pace & Rozefelds for a Northern Hemisphere fossil wood is also proposed. Austrovideira and Stafylioxylon share with Vitaceoxylon secondary xylem with two diameter classes of vessels, wide vessels usually solitary, narrow vessels forming radial chains, very wide and tall rays, scanty paratracheal parenchyma and septate fibres. Austrovideira differs from Vitaceoxylon in having scalariform intervessel pits and homocellular rays composed exclusively of procumbent cells. This combination of features is seen in the Ampelocissus‐Vitis clade, and a clearly stratified phloem with fibre bands alternating with all other axial elements and phloem rays rapidly dilating towards the periderm is restricted to Parthenocissus and Vitis. Stafylioxylon shares with Austrovideira the presence of scalariform intervessel pits but it differs from that genus in both ray composition and bark anatomy, as it lacks a stratified phloem. These fossil wood genera demonstrate that the lianescent habit in the Vitaceae was established by the Eocene in the Northern Hemisphere and by the Oligocene in the Southern Hemisphere. The pollen and seed fossil record shows that the Vitaceae were in Australia by the Eocene and fossil seeds suggest that the family had radiated by this time. The Oligocene Capella flora with two seed taxa and fossil wood (Austrovideira) provides further evidence of an Australian radiation. The fossil evidence, suggests a significant Gondwanic history for the family.  相似文献   

4.
Dicotyledonous woods from the Upper Cretaceous of Southern IllinoiS. Five species of fossil dicotyledonous wood are described from an Upper Cretaceous (Maestrichtian; locality in Alexander County, IllinoiS. U.S. A. Paraquercimum cretaceum has structure similar to the Fagaceae (evergreen Oak- Lithocarpus ) and Casuarinaceae and represents the earliest known occurrence of this structural type (large solitary pores and uniseriate and large multiseriale rays). Paraphyltanthoxyhin illirioisense and Icacinoxylon alternipunctata are species of genera represented at other Cretaceous and Early Tertiary localities In large diameter trees. Parabombacaceoxylon magniporosum has large diameter pores and scalariform perforation plates, a combination of characters that is extremely rare in the extant flora. Paraapocynaceoxylon barghoorni has a combination of characters represented in extant Apocynaceae. These five species lack growth rings, have high vulnerability indices (mean vessel diameter divided by mean number of vessels per square millimeter, and a relatively high proportion of ray parenchyma. They lack specialized wood anatomical characters, and a compilation of vessel element lengths in these and other Cretaceous woods indicates that short vessel elements (a derived character) were less frequent in the Cretaceous than in extant dicotyledonous trees.  相似文献   

5.
A new genus is recognized on the basis of wind-dispersed fruits from the Eocene of western North America and Miocene of eastern Asia. The fruits consist of an accrescent hypogynous calyx of five obovate sepals and one or more globose fruit bodies. Although the fossils were formerly placed in the extant genera Porana (Convolvulaceae) and Astronium (Anacardiaceae), our investigation of numerous specimens from several floras in the western United States (e.g., Florissant, Green River, Clarno) and Canada (Whipsaw Creek, British Columbia) and the Yilan and Shanwang floras of China reveals unique characters that indicate that the fossils are a distinct genus, which we name Chaneya. Unlike Porana and Astronium, the fossil calyces have stomata that are longitudinally aligned, and early stages of fruit development show a gynoecium of five apocarpous carpels, of which only one or two usually enlarge at maturity. Precise systematic placement of the fossil genus is uncertain, but similarities to the extant Picrasma of the Simaroubaceae are suggestive of possible affinities. Two species are recognized: Chaneya tenuis (Lesq.) comb. nov., from the Eocene of western North America and northeastern China, and Chaneya kokangensis (Endo) comb. nov., from the Miocene of eastern Asia.  相似文献   

6.
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.  相似文献   

7.
Scott , R. A., E. S. Barghoorn , and U. Prakash . (U.S. Geol. Sur., Denver, Colo.) Wood of Ginkgo in the Tertiary of western North America . Amer. Jour. Bot. 49(10): 1095–1101. Illus. 1962. —Woods of Ginkgo and extinct related genera are very rare in the fossil record in contrast to the numerous ginkgoalean leaves. Ginkgo wood may be distinguished from other gymnosperms by a combination of anatomical features herein described. Ginkgo wood from beds of Miocene age at Vantage, Washington, first identified by Beck, is assigned to a new species, G. beckii. Ginkgo wood from the upper Eocene Clarno Formation, John Day Basin, Oregon, is described as G. bonesii sp. nov. Scarcity of fossil ginkgoalean woods may reflect unusual susceptibility to degradation of their cell walls in contrast to the greater chemical resistance to degradation which features many coniferous woods.  相似文献   

8.
Wood anatomy of 16 collections representing three species containing eight subspecies of the single genusDaphniphyllum is analyzed quantitatively and qualitatively.Daphniphyllum has vessels angular to roundish in transection, scalariform perforation plates, scalariform to opposite lateral wall vessel pitting, tracheids with fully bordered pits, heterocellular multiseriate and uniseriate rays, diffuse axial parenchyma and, in one taxon, chambered crystals in axial parenchyma cells. Growth rings, narrower vessels, and more numerous, vessels per square mm characterize taxa from cooler habitats. All of the taxa have highly mesomorphic woods. Comparisons are made between Daphniphyllaceae and the other families of Thorne's Pittosporales (Balanopaceae, Bruniaceae, Buxaceae, Byblidaceae, Geissolomataceae. Grubbiaceae, Myrothamnaceae, Pittosporaceae, Roridulaceae, and Tremandraceae). These families are most comparable to hamamelidoid or rosoid families; other similarities or relationships for these families may exist, but are less conspicuous or less close. The families cited may form a plexus, characterized by primitive xylary and other features, comparable to Annonales (Magnoliales) as products of an early radiation of dicotyledons.  相似文献   

9.
Cercidiphylloxylon spenceri(Brett)Pearson is described from the Lizigou Formation,Palaeocene in China.The growth rings are distinct; pores are diffuse,solitary,with somewhat angular outlines in cross section;vessel elements long with long scalariform perforation plates; intervessel pitting is opposite to scalariform; fibertracheids are present; axial parenchyma is scarce; rays are mostly biseriate and heterogeneous.All wood characters of the fossil specimen fall into the range of those of extant Cercidiphyllum(Cercidiphyllaceae).The finding is one of the earliest fossil wood records of Cercidiphyllaceae.  相似文献   

10.
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.  相似文献   

11.
Wood anatomy ofCoriaria was surveyed to clarify generic features on the basis of 14 species collected from various regions of the World to cover the whole range of geographic distribution and habitual variation. Wood anatomy ofcoriaria is considerably uniform, and the species share a combination of the following features: 1) pores are thin-walled, polygonal in outline and mostly in multiples; 2) vessel elements and libriform fibers are very short; 3) perforation plates are exclusively simple; 4) intervessel pits are alternate; 5) vascular tracheids are present; 6) wood parenchyma is vasicentric and sometimes confluent; 7) rays are heterogeneous and large. Its species differ in several characters, such as distinctness of growth rings, pore size, pore patterns, type and abundance of wood parenchyma, and distinctness of storied structure. Comparisons among species indicate that the species of the Northern Hemisphere show a tendency toward having semi-ring porosity, while those of the Southern and Western Hemisphere have diffuse porosity. The other infrageneric variations appear to be related to different habits of the species rather than to geographic distribution. Small trees mostly have confluent and vasicentric parenchyma composed of fusiform cells and distinctly storied tissues, while shrubs and herbs have less abundant parenchyma which is vasicentric and comprises strands of two to four cells and indistinctly storied tissues.  相似文献   

12.
In this paper, we describe a new species Magnolia nanningensis sp. nov., based on exceptionally well‐preserved mummified fossil woods from the late Oligocene of the Nanning Basin, Guangxi, South China. The features of these woods indicate a close affinity to the section Michelia of the subgenus Yulania belonging to the genus Magnolia sensu lato (Magnoliaceae). Magnolia nanningensis is the first fossil record of the section Michelia from China, the modern diversity center of this group. These mummified woods provide fossil evidence supporting molecular dating that estimated an Oligocene age for divergence of the tropical evergreen section Michelia and the temperate deciduous section Yulania. Helical thickenings on vessel walls and a high degree of vessel grouping found in these fossil woods could be adaptive to temporary, possibly seasonal, droughts and, as suggested by other woods from the Nanning Basin, could be indicative of a monsoon‐influenced tropical climate in Guangxi during the late Oligocene. Helical thickenings have not been reported in magnoliaceous fossil woods prior to the Oligocene. The appearance of this trait was presumably a response to abrupt climate cooling near the Eocene–Oligocene boundary, followed by increase in climate seasonality. The associated increase of latitudinal zonation might be a possible trigger for divergence between the tropical evergreen sect. Michelia and the temperate deciduous sect. Yulania.  相似文献   

13.
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  相似文献   

14.
Abstract Cercidiphylloxylon spenceri (Brett) Pearson is described from the Lizigou Formation, Palaeocene in China. The growth rings are distinct; pores are diffuse, solitary, with somewhat angular outlines in cross section; vessel elements long with long scalariform perforation plates; intervessel pitting is opposite to scalariform; fiber‐tracheids are present; axial parenchyma is scarce; rays are mostly biseriate and heterogeneous. All wood characters of the fossil specimen fall into the range of those of extant Cercidiphyllum (Cercidiphyllaceae). The finding is one of the earliest fossil wood records of Cercidiphyllaceae.  相似文献   

15.
The families Achariaceae and Salicaceae (Malpighiales) are characterized by wood anatomical ranges that partly overlap. Formerly these families were treated together in the polyphyletic Flacourtiaceae and a much more narrowly circumscribed Salicaceae. Here we attribute two recently collected fossil woods from the Deccan Intertrappean Beds to the clade that contain these two families, i.e., the Parietal Clade of the Malpighiales. The new genus Elioxylon shares features with several extant genera of Achariaceae and Salicaceae, but does not completely match with any of them. A new record of Hydnocarpoxylon indicum Bande & Khatri is a good match for extant Hydnocarpus Gaertn. (Achariaceae). Elioxylon and Hydnocarpoxylon share an absence of parenchyma, the presence of septate fibres and 1–3 seriate heterocellular rays with long uniseriate margins consistent with Achariaceae and Salicaceae. Elioxylon has mixed simple and scalariform perforations, whereas Hydnocarpxylon has exclusively scalariform perforations. Other Deccan fossils formerly attributed to “Flacourtiaceae” in the literature are critically discussed and mostly excluded from Achariaceae and Salicaceae. Elioxylon and Hydnocarpoxylon from the Maastrichtian ‐ Danian of India are the oldest fossil records of the Parietal Clade of the Malpighiales. With their occurrence on the Indian plate during its northward journey from Gondwana to Laurasia, these fossils provide further support for an ‘out‐of‐India’ hypothesis for Achariaceae and/or Salicaceae. “Baileyan trends” in vessel perforation plate and vessel grouping evolution are apparent in the phylogeny of the Parietal Clade.  相似文献   

16.
A vesselless fossil wood was discovered in the Miocene Yanagida Formation in the Noto Peninsula, central Japan. This fossil has distinct growth rings with gradual transition from the early- to the latewood ; tracheids, which are called 'usual traeheids' here, constitute the ground mass of the wood and have typical scalariform bordered pits on radial walls in the earlywood and circular sparse pits on those in the latewood ; rays are 1\2-4 cells wide and heterogeneous with low to high uniseriate wings; axial parenchyma strands are scattered in the latewood. This wood has a peculiar feature; sporadic radial files of broad tracheids whose tangential walls have crowded alternate bordered pits. The radial walls have crowded half-bordered pits to ray cells, but no pits to the usual tracheids. Among all of the extant and extinct angiosperms and gymnosperms, these unusual tracheids occur only in Tetracentron. From these features, we refer the fossil to the extant genus Tetracentron, and name it T. japonoxylum. A revision of homoxylic woods is made for comparision with the present fossil. Tetracentron japonoxylum is the only fossil wood of Tetracentron.  相似文献   

17.
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.  相似文献   

18.
The very different evolutionary pathways of conifers and angiosperms are very informative precisely because their wood anatomy is so different. New information from anatomy, comparative wood physiology, and comparative ultrastructure can be combined to provide evidence for the role of axial and ray parenchyma in the two groups. Gnetales, which are essentially conifers with vessels, have evolved parallel to angiosperms and show us the value of multiseriate rays and axial parenchyma in a vessel-bearing wood. Gnetales also force us to re-examine optimum anatomical solutions to conduction in vesselless gymnosperms. Axial parenchyma in vessel-bearing woods has diversified to take prominent roles in storage of water and carbohydrates as well as maintenance of conduction in vessels. Axial parenchyma, along with other modifications, has superseded scalariform perforation plates as a safety mechanism and permitted angiosperms to succeed in more seasonal habitats. This diversification has required connection to rays, which have concomitantly become larger and more diverse, acting as pathways for photosynthate passage and storage. Modes of growth such as rapid flushing, vernal leafing-out, drought deciduousness and support of large leaf surfaces become possible, advantaging angiosperms over conifers in various ways. Prominent tracheid-ray pitting (conifers) and axial parenchyma/ray pitting to vessels (angiosperms) are evidence of release of photosynthates into conductive cells; in angiosperms, this system has permitted vessels to survive hydrologic stresses and function in more seasonal habitats. Flow in ray and axial parenchyma cells, suggested by greater length/width ratios of component cells, is confirmed by pitting on end walls of elongate cells: pits are greater in area, more densely placed, and are often bordered. Bordered pit areas and densities on living cells, like those on tracheids and vessels, represent maximal contact areas between cells while minimizing loss of wall strength. Storage cells in rays can be distinguished from flow cells by size and shape, by fewer and smaller pits and by contents. By lacking secondary walls, the entire surfaces of phloem ray and axial phloem parenchyma become conducting areas across which sugars can be translocated. The intercontinuous network of axial parenchyma and ray parenchyma in woods is confirmed; there are no “isolated” living cells in wood when three-dimensional studies are made. Water storage in living cells is reported anatomically and also in the form of percentile quantitative data which reveal degrees and kinds of succulence in angiosperm woods, and norms for “typically woody” species. The diversity in angiosperm axial and ray parenchyma is presented as a series of probable optimal solutions to diverse types of ecology, growth form, and physiology. The numerous homoplasies in these anatomical modes are seen as the informative results of natural experiments and should be considered as evidence along with experimental evidence. Elliptical shape of rays seems governed by mechanical considerations; unusually long (vertically) rays represent a tradeoff in favor of flexibility versus strength. Protracted juvenilism (paedomorphosis) features redirection of flow from horizontal to vertical by means of rays composed predominantly or wholly of upright cells, and the reasons for this anatomical strategy are sought. Protracted juvenilism, still little appreciated, occurs in a sizeable proportion of the world’s plants and is a major source of angiosperm diversification.  相似文献   

19.
Seeds are useful in distinguishing among extant genera of Vitaceae and provide a good basis for interpretation of fossil remains in reconstructing the evolutionary and phytogeographic history of this putatively basal Rosid family. Seeds of Ampelocissus s.l. including Pterisanthes and Nothocissus are distinguished from those of all other vitaceous genera by long, parallel ventral infolds and a centrally positioned oval chalazal scar. Principal component analysis facilitates recognition of four Ampelocissus s.l. seed morphotypes differentiated by dorsiventral thickness, width of ventral infolds, chalazal depth, and degree of dorsal surface rugosity. While these intergrade, their end-member morphologies are distinctive and coincide well with inflorescence morphology, extant geographic distribution, and ecology. Seven fossil morphospecies are recognized. Ampelocissus parvisemina sp. n. (Paleocene of North Dakota; Eocene of Oregon) and A. auriforma Manchester (Eocene of Oregon) resemble extant Central American species; A. bravoi Berry (Eocene of Peru) is similar to one group of Old World extant species; and A. parachandleri sp. n. (Eocene of Oregon) and the three European fossil species A. chandleri (Kirchheimer) comb. n., A. lobatum (Chandler) comb. n., and A. wildei sp. n. (Eocene to Miocene) resemble another group of extant Old World Ampelocissus. All these fossils occur outside the present geographic range of the genus, reflecting warmer climates and former intercontinental links.  相似文献   

20.
Previous analyses ofAsteropeia andPhysena have not compared the wood anatomy of these genera to those of Caryophyllales s.l. Molecular evidence shows that the two genera from a clade that is a sister group of the core Caryophyllales. Synapomorphies of theAsteropeia-Physena clade include small circular alternate pits on vessels, presence of vasicentric tracheids plus fiber-tracheids, presence of abaxial-confluent plus diffuse axial parenchyma, and presence of predominantly uniseriate rays. These features are analyzed with respect to habit and ecology of the two genera. Solitary vessels, present in both genera, are related to the presence of vasicentric tracheids. Autapomorphies in the two genera seem related to adaptations byPhysena as a shrub of moderately dry habitats (e.g., narrower vessel elements, abundant vasicentric tracheids, square to erect cells in rays) as compared to alternate character expressions that seem related to the arboreal habit and humid forest ecology ofAsteropeia. The functional significance of vasicentric tracheids and fiber-tracheids in dicotyledons is briefly reviewed in the light of wood anatomy of the two genera.  相似文献   

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