Betulaceous leaves and fruits from the British Upper Palaeocene

Fossil leaves and bracteate fruits are described from a new Upper Palaeocene locality in the Reading Beds near Newbury, southern England. The leaves are assigned to Craspedodromophyllum acutum Crane and correspond in many respects to those of living Betulaceae. The bracts and fruits are assigned to Palaeocarpinus laciniata Crane, which although referable to the Coryleae exhibits a novel combination of the characters of several living genera, particularly Corylus and Carpinus. An argument is presented for the association of these organs as a reconstructed fossil plant which is an extinct member of the Betulaceae. The evolution and fossil record of the Betulaceae are discussed, the late Upper Cretaceous and Palaeocene being regarded as the time at which the characters of modern genera were beginning to differentiate. Carpinus appears to have undergone a major Eurasian diversification during the late Palaeogene and early Neogene. Dispersal in Palaeocarpinus laciniata was probably less specialized than in most extant Coryleae.     

Complete congruence between morphological and rbcL-based molecular phylogenies in birches and related species (Betulaceae).

Estimations of phylogenies from morphological and molecular data often show contrasting results. We compared morphological and molecular phylogenies in an ancient family of woody dicots, the Betulaceae (birch family). The phylogeny of the family was estimated from parsimony analysis of morphological characters in the genera Alnus, Betula, Carpinus, Corylus, Ostrya, and Ostryopsis and from parsimony and distance-matrix analyses of DNA sequences of the chloroplast gene encoding the large subunit of ribulose-1,5-biphosphate carboxylase (rbcL) in the genera Alnus, Betula, Carpinus, Corylus, and Ostrya and in two outgroups, Quercus and Liquidambar. The topologies obtained by the different methods were completely congruent, and bootstrapping strongly supported the division of the family Betulaceae into two major clades, Betuleae (Alnus and Betula) and Coryleae (other members). Only slightly more homoplasy was present in the rbcL sequence data set than in the morphological set. Relative-rate tests indicated that the Coryleae clade had a faster rate of rbcL evolution than did the Betuleae clade. Heterogeneity of rates of morphological evolution also paralleled those for rbcL.     

A Study on Foliar Epidermis in Betulaceae

Light and scanning electron microscopes were used to examine foliar epidermal features such as the shape of epidermal cells, the type of stomatal apparatus and outer stomatal rim in 38 species of 6 genera of the Betulaceae. Four types of stomatal apparatus on mature leaves are recognized in this survey: anomocytic, cyclocytic, non-typical actinocytic and brachyparacytic. The foliar epidermal characters and character states are taxonomically useful for the identification of genera and the division of tribes. The generalized evolutionary scheme for foliar epidermal features is fairly closely correlated with the generic relationships proposed in other studies (Abbe, 1935, 1974; Brunner & Fairbrothers, 1979; Hall, 1952; Kikuzava, 1982; Kuprianova, 1963)and it is clear that foliar epidermal morphology can be an important taxonomic character added to others for determining evolutionary relationships. The explanations of generic relationships are based on our hypothesis that anomocytic stomatal apparatus, uni-layered outer stomatal rim, having not T-pieces at the polar region of guard cells and straight anticlinal wall of lower epidermal cell are from the ancestor (Fig. 1). Sinuolate or sinuate anticlinal wall of lower epidermal cells and non-typical actinocytic stomatal apparatus, present in Corylus, Ostryopsis, Ostrya and Carpinus of the Betulaceae, correlates with the separation of Coryleae from Betuleae. Betuleae including Alnus and Betula is considered primitive with more primitive characters. Of Coryleae, Carpinus might be the most advanced, with brachyparacytic stomatal apparatus and double-layered outer stomatal rim.     

A re-evaluation of Cercidiphyllum-like plant fossils from the British early Tertiary

The occurrence of Cercidiphyllum -like leaves, infructescences, fruits and seeds in the British early Tertiary is reviewed. Material previously described from the London Clay Formation, Lower Headon Beds (upper Barton Formation), Oldhaven Formation, and Woolwich and Reading Formation, are evaluated along with specimens from a new late Palaeocene locality in the Reading Beds. The leaves are assigned to Trochodendroides prestwichii; and infructescences, fruits and seeds, previously assigned to Carpolithus gardneri and Jenkinsella apocynoides , are united as a single species Nyssidium arcticum. The evidence that Trochodendroides and Nyssidium are parts of a single kind of fossil plant is supported, and the reconstructed ' Nyssidium plant' is compared with extant taxa, particularly extant Cercidiphyllum. The fossil plant shows a combination of characters not seen in any living genus, and the structure of the infructescence, as well as other features, precludes placing it within Cercidiphyllum. 'Nyssidium' and Cercidiphyllum are closely related. The morphological and sedimentological evidence indicates that 'Nyssidium' was an important colonizer of a variety of open flood-plain environments during the early Tertiary.     

Harvesting Betulaceae sequences from GenBank to generate a new chronogram for the family

Betulaceae, with 120–150 species in six genera, are a family of Fagales that occurs mainly in the Northern Hemisphere. Previous studies of the evolution of Alnus, Betula, Carpinus, Corylus, Ostrya and Ostryopsis have relied on a relatively small number of sequence data and molecular clocks with fixed‐point calibrations. We exploited GenBank to construct Betulaceae matrices of up to 900 sequence accessions and 9300 nucleotides of nuclear and plastid DNA; we also computed species consensus sequences to build 46‐ and 29‐species matrices that strike a balance between species sampling and nucleotide sampling. Trees were rooted on Ticodendraceae and Casuarinaceae, and divergence times were inferred under relaxed and strict molecular clocks, using alternative fossil constraints. The data support the traditional two subfamilies, Betuloideae (Alnus, Betula) and Coryloideae, and show that Ostryopsis is sister to Ostrya/Carpinus. The fossil record and molecular clocks calibrated with alternating fossils indicate that the stem lineage of Betulaceae dates back to the Upper Cretaceous, the two subfamilies to the Palaeocene and the most recent common ancestors of each of the living genera to the mid‐ to late Miocene. A substitution rate shift in Coryloideae between 25 and 15 Mya preceded the mid‐Miocene climatic optimum and may be linked to temperate niches that became available following the mid‐Miocene. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172 , 465–477.     

Fossil woods from the Lower Coal-bearing Formation of the Janggi Group (Early Miocene) in the Pohang Basin,Korea

Fourteen species of fossil wood belonging to eleven genera and seven families were identified from 38 well preserved specimens collected from the Lower Coal-bearing Formation of Janggi Group at Donghae-myeon, Pohang City, Gyeongsangbuk-do Prefecture, Korea. Seven new taxa were found and described; they are Carya koreana Jeong et Kim, Betula janggiensis Jeong et Kim, Carpinus donghaensis Jeong et Kim, Ostrya geumgwangensis Jeong et Kim, Stewartia pseudo-camellioxylon Jeong et Kim, Acer minokamoensis Jeong, Kim et Suzuki and Acer pohangensis Jeong et Kim. The most abundant taxa are Betulaceae, Aceraceae, Ulmaceae, and Wataria. Except Wataria of which the habitat preference has not been confirmed, these taxa are major elements of cool-temperate vegetation and are similar to the Aniai-type flora of Japan. Previous studies of fossil plants from the Geumgwangdong Shale (leaves and seeds), the Upper Coal-bearing Formation (fossil woods) and the Yeonil Group (leaves and seeds) and this study, show that the climate of the Pohang Basin changed from cool-temperate to warm-temperate and subtropical during the Miocene.     

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.     

Feuilles et involucres fructifères de Carpinus L. du gisement pliocène de pichegu près de Saint-Gilles (Gard): Comparaison avec les Charmes tertiaires et quaternaires

The Pliocene flora from Pichegu yields numerous plant remains, especially leaves and involucres of the genus Carpinus. A morphological and biometrical study revealed two types: Carpinus betulus with small fruits and small leaves and Carpinus orientalis. These populations evolved during the Upper Pliocene and Pleistocene under the influence of cooling and dryness of the climate.     

Phylogeny and evolution of the Betulaceae as inferred from DNA sequences,morphology, and paleobotany

Phylogeny of the Betulaceae is assessed on the basis of rbcL, ITS, and morphological data. Based upon 26 rbcL sequences representing most “higher” hamamelid families, the Betulaceae are monophyletic, with Casuarinaceae as its sister group, regardless of whether the outgroup is Cunoniaceae, Cercidiphyllaceae, Hamamelidaceae, or Nothofagus. Within the Betulaceae, two sister clades are evident, corresponding to the subfamilies Betuloideae and Coryloideae. However, with only 13 phylogenetically informative sites, the rbcL sequences provide limited intra-subfamilial resolution. Internal transcribed spacer (ITS) sequences provided 96 phylogenetically informative sites from 491 aligned sites resulting in a single most parsimonious tree of 374 steps (consistency index = 0.791) with two major lineages corresponding to the two traditional subfamilies: Betuloideae (Alnus, Betula) and Coryloideae (Corylus, Ostryopsis, Carpinus, Ostrya). This arrangement is mostly consistent with those from rbcL and morphology and is greatly reinforced by analyses with the three data sets combined. In the Coryloideae, the Ostryopsis–Carpinus–Ostrya clade is well supported, with Corylus as its sister group. The sister-group relationship between Ostryopsis and the Carpinus–Ostrya clade is well supported by ITS, rbcL, and morphological data. Phylogenetic relationships among the extant genera deduced by these analyses are compatible with inferences from ecological evolution and the extensive fossil record.     

THE PLATYCARYA PERPLEX AND THE EVOLUTION OF THE JUGLANDACEAE

We report on the leaves, fruits, inflorescences, and pollen of two fossil species in the genus Platycarya. The association of these dispersed organs has been established by their repeated co-occurrence at a large number of localities, and for two of the organs (fruit and pistillate inflorescence, and pollen and staminate inflorescence) by apparent organic attachment of compression fossils. Each of the two species can be distinguished by characteristics of all the known megafossil organs. We also review the fossil record of dispersed platycaryoid fruits and inflorescences, recognizing three additional species of Platycarya and two of Hooleya. Two of the fossil Platycarya species are morphologically very different from the living Platycarya strobilacea Sieb. et Zucc., but they show the diagnostic features of the genus. Hooleya is a generalized member of the Platycaryeae that is probably close to the ancestry of Platycarya. The two Platycarya species known from multiple organs provide a remarkable example of mosaic evolution in which fertile and foliar structures have attained different levels of morphological specialization. The leaves, often considered the most plastic of plant organs, retain several features that are otherwise seen only in the Engelhardieae. These similarities in leaf architecture between the fossil Platycarya species and Engelhardieae are advanced features for the Juglandaceae, and thus indicate a sister-group relationship between the two lines. In contrast to the leaves, the fruits, inflorescences, and pollen of the fossil Platycarya species are almost as specialized as those of the extant P. strobilacea and bear little resemblance to the same structures in other genera of the family. The morphology, taphonomy, sedimentary setting, and geographic and stratigraphic distribution of three of the fossil platycaryoid species suggest that they were wind-dispersed, early successional plants that grew in thickets. This habit is retained by Platycarya strobilacea and is typical of many of the amentiferae (e.g. Myricaceae, Betulaceae). The r-selected life-history pattern of the Platycarya line may well have contributed to its low diversity through geologic time.     

Wuyunanthus gen. nov., a flower of Celastraceae from the Palaeocene of north-east China

A flower assigned to Wuyunanthus hexapetalus gen. & sp. nov. has been collected from the Wuyun Formation of Palaeocene age, Jiayin County, Heilongjiang Province, north-east China. The flower is bisexual, actinomorphic, and 6-merous. There are six free valvate petals in a whorl inserted on the margin of a hexagonal disk, and six free stamens alternate with petals within it. The pistil consists of fused carpels. Ovary with an apical style is superior. The unique combination of characters of the fossil, such as stamens inside the thick and flattened disk surrounding the ovary and equal in number to the petals, is similar to that of Celastraceae. The fossil is assigned to Celastraceae but distinguished from other extant genera of the family by being 6-merous rather than 4- or 5-merous. It might represent an extinct and early type of Celastraceae. The presence of a disk might provide evidence for insect pollination in the early stages of Celastraceae evolution.     

Phylogenetic Distribution and Identification of Fin-winged Fruits

Fin-winged fruits have two or more wings aligned with the longitudinal axis like the feathers of an arrow, as exemplified by Combretum, Halesia, and Ptelea. Such fruits vary in dispersal mode from those in which the fruit itself is the ultimate disseminule, to schizocarps dispersing two or more mericarps, to capsules releasing multiple seeds. At least 45 families and more than 140 genera are known to possess fin-winged fruits. We present an inventory of these taxa and describe their morphological characters as an aid for the identification and phylogenetic assessment of fossil and extant genera. Such fruits are most prevalent among Eudicots, but occur occasionally in Magnoliids (Hernandiaceae: Illigera) and Monocots (Burmannia, Dioscorea, Herreria). Although convergent in general form, fin-winged fruits of different genera can be distinguished by details of the wing number, texture, shape and venation, along with characters of persistent floral parts and dehiscence mode. Families having genera with fin-winged fruits and epigynous perianth include Aizoaceae, Apiaceae, Araliaceae, Asteraceae, Begoniaceae, Burmanniaceae, Combretaceae, Cucurbitaceae, Dioscoreaceae, Haloragaceae, Lecythidiaceae, Lophopyxidaceae, Loranthaceae, and Styracaceae. Families with genera having fin-winged fruits and hypogynous perianth include Achariaceae, Brassicaceae, Burseraceae, Celastraceae, Cunoniaceae, Cyrillaceae, Fabaceae, Malvaceae, Melianthaceae, Nyctaginaceae, Pedaliaceae, Polygalaceae, Phyllanthaceae, Polygonaceae, Rhamnaceae, Salicaceae sl, Sapindaceae, Simaroubaceae, Trigoniaceae, and Zygophyllaceae. This survey has facilitated the identification of fossil winged fruits such as Combretaceae and Araliaceae in the late Cretaceous of western North America and provides additional evidence toward the identification of various Cenozoic fossils including Brassicaceae, Fabaceae, Polygonaceae, Rutaceae, and Sapindaceae.     

Comparative Flower and Inflorescence Organogenesis among Genera of Betulaceae: Implications for Phylogenetic Relationships

Betulaceae have simple flowers but complex inflorescences. Recent phylogenetic analyses using molecular data have produced robust phylogenetic trees of Betulaceae. In this study, we evaluated the phylogenetic value of comparative organogenetic data of reproductive organs in the context of molecular phylogenies. Flower and inflorescence developmental processes of 21 species from all six genera in Betulaceae were documented with scanning electron microscopy. In each pistillate cyme, there are one primary bract, two secondary bracts, and two or three flowers in the six genera; only in Alnus are there two tertiary bracts on the abaxial side. The pistillate flower of all genera but Alnus has tepal primordia. Two tepals stop developing early on, resulting in the lack of tepals in mature flowers of Betula; while the tepals are initiated from a common circular primordium at the base of pistil in Corylus, Ostryopsis, Carpinus, and Ostrya, and the developed tepals with irregular shape and unstable number of lobes are adnate to the top of the pistil. In staminate organogenesis, each cyme has one primary bract and three flowers in all genera; two secondary bracts are only present in Alnus, Betula, and Corylus. Staminate flowers have no tepals except in Alnus and Betula, and exhibit high variation in number of stamens among genera. The number of secondary and tertiary bracts in each pistillate and staminate cyme, as well as the presence of tepals in pistillate and staminate flowers was clarified in all genera. Micro-morphological characters were used to infer the phylogenetic relationships of genera and sections of Betulaceae. Our analyses support the division of two subfamilies: Betuloideae (Alnus and Betula) and Coryloideae (Corylus, Carpinus, Ostrya, and Ostryopsis), and three tribes: Betuleae (Alnus and Betula), Coryleae (Corylus), and Carpineae (Carpinus, Ostrya, and Ostryopsis). The results agree with those from molecular phylogenetic studies, and suggest that micro-morphological characters are phylogenetically informative in Betulaceae, and reproductive organs of Betulaceae have evolved in the direction of reduction in bracts and tepals.     

Plastomes of Betulaceae and phylogenetic implications

Betulaceae is a well‐defined family of Fagales, including six living genera and more than 160 modern species. Species of the family have high ecological and economic value for the abundant production of wood. However, phylogenetic relationships within Betulaceae have remained partly unresolved, likely due to the lack of a sufficient number of informative sites used in previous studies. Here, we re‐investigate the Betulaceae phylogeny with whole chloroplast genomes from 24 species (17 newly assembled), representing all genera of the family. All the 24 plastomes are relatively conserved with four regions, and each genome is ∼158–161 kb long, with 111 genes. The six genera are all monophyletic in the plastome tree, whereas Ostrya Scop. is nested in the Carpinus clade in the internal transcribed spacer tree. Further incongruencies are also detected within some genera between species. Incomplete lineage sorting and/or hybrid introgression during the diversification of the family could account for such incongruencies. Our dating analysis, based on four fossils, suggests that the most recent common ancestors of the extant genera date back to the mid‐ to late Miocene, and confirms that Betulaceae started to diversify in the upper Cretaceous/early Paleocene. Our results highlight the significance of using more informative sites in resolving phylogenetic relationships. Plastome data and increased taxon sampling will help to better understand the evolutionary history of Betulaceae in the future.     

A NEW CONIFER FROM THE UPPER CRETACEOUS OF CENTRAL CALIFORNIA

Stems with inner bark, wood, pith, and leaves from the Upper Cretaceous (Maastrichtian) of central California are described. The name Margeriella cretacea gen. et sp. n. is assigned to the fossils. The leaves are long, narrow, spirally arranged, and each contains three resin canals, a thick vascular sheath, and a dense mesophyll. Only first-year wood is present in the stem. The large pith is composed of large cells among which are scattered clusters of even larger darkly colored cells. Leaf epidermis and wood characters suggest affinities with the Taxodiaceae, but the structure of the pith and the internal structure of the leaves have no counterpart among modern or known fossil members of that family. The fossil is regarded as an extinct form possibly belonging to the large taxodioid complex thought by some workers to have existed in the Mesozoic.     

Fossil evidence of interactions between plants and plant-eating mammals.

We document changes in mammalian dietary and foraging locomotor adaptation, and appearances and developments of angiosperm fruiting strategies and vegetation types since the late Cretaceous in the Euramerican region, and to some extent in low latitude Africa. These changes suggest: (i): an expansion in the exploitation of dry fruits and seeds by mammals on the ground as well as in the trees after the terminal Cretaceous dinosaur extinction; (ii) a relation between large nuts and rodents, which appear in the late Palaeocene and radiate in the late Eocene; (iii) a relation between primates and fleshy fruits established in the early-Middle Eocene when tropical forests reached their maximum latitudinal extent; (iv) a hiatus of several million years in the vertebrate exploitation of leaves after dinosaur extinction and before the first few mammalian herbivores in the Middle Palaeocene, followed by an expansion in the late Eocene when climates cooled and more open vegetation became established.     

ATTACHED LEAVES,INFLORESCENCES, AND FRUITS OF FAGOPSIS,AN EXTINCT GENUS OF FAGACEOUS AFFINITY FROM THE OLIGOCENE FLORISSANT FLORA OF COLORADO,U.S.A.

Specimens showing staminate and pistillate inflorescences attached to branches bearing Fagopsis longifolia (Lesq.) Hollick foliage, from the Oligocene Florissant flora of Colorado, permit a relatively complete characterization of the extinct Fagopsis plant. The alternately arranged simple leaves have pinnate craspedodromous venation and prominent simple teeth. Staminate inflorescences are globose on a stout peduncle and contain anthers with tricolporate pollen. Pistillate inflorescences are ovoid heads with compact, helically arranged three-flower units and are interpreted to have three styles per flower. The infructescence consists of small wedge-shaped cupules, each containing three tiny fruits, and subtended by a persistent bract. The cupules unravel from the swollen peduncle at maturity and are often dispersed as strings of adhering fruit-wedges which frequently take on a regular, more or less circular appearance. Fagopsis is unlike any living genus but has characters which support a relationship to the Fagaceae. Unlike extant members of the family, which typically have fruits adapted for animal dispersal, Fagopsis is less obviously specialized and perhaps adapted for wind dispersal. The striking differences in fruiting structures between Fagopsis and extant Fagaceae parallel the differences between the extant genera Platycarya and Juglans in the Juglandaceae, and Alnus and Corylus in the Betulaceae.     

The Gomphaeschninae (Odonata: Aeshnidae): new fossil genus, reconstructed phylogeny, and geographical history

ABSTRACT. Three new species of fossil Anisoptera (dragonflies) are reported from Tiffanian (Late Palaeocene) sediments of the Paskapoo Formation, near Red Deer, Alberta, Canada. The three species are all assigned to the new genus Alloaeschna , which is classified in the subfamily Gomphaeschninae.
Phylogenetic analysis of gomphaeschnine wing venation suggests that the subfamily is paraphyletic, with derived gomphaeschnines such as Boyeria and Linaeschna more closely related to the Brachytroninae and Aeshninae than are other gomphaeschnines. One of the most primitive gomphaeschnines, and the oldest fossil form, is the Jurassic Morbaeschna. Parallelism, convergence and reversal in the evolution of features of the wing venation is common.
The new genus Alloaeschna is at about the same evolutionary grade as the old-world genus Oligoaeschna and the new-world genus Gomphaeschna , and is one of the more primitive known members of the Gomphaeschninae. The new species are the first recorded Palaeocene gomphaeschnines and the oldest known gomphaeschnines from the Americas.
Several extant genera have fossil representatives on continents different from those on which they now survive, suggesting repeated crossing of land bridges and/or widespread ancestral species prior to the separation of the continents, and subsequent extinction leading to present relict distributions.     

Fossil Cycadales of Argentina

A survey of Cycadalean taxa of Argentina (including Antarctica) is presented. The record of leaves represented byNilssonia, Pseudoctenis, Ctenis, Mesodescolea, Ticoa, Almargemia,Kurtziana, andZamia genera are summarized. Recent investigations made of cuticles with transmission and scanning electron microscopy are included. In stems, a preliminary study of two forms found in the Upper Cretaceous of Rio Negro Province are incorporated intoMichelilloa, Bororoa, andMenucoa. The fossil record shows some characters of leaf morphology, presence of inverse xylem and medullary bundles, two kinds of leaf traces, and monoxylic and polyxylic steles of systematic importance when compared with both extant and fossil cycads. Affinities of fossil taxa related to extant families are suggested through analysis of the above-mentioned characters. The presence of medullary vascular rings related to the emission of terminal reproductive strobili are recognized inBororoa andMenucoa. This character associated with polyxyly makes it possible to assign these genera to the Zamiaceae-Encephalartoideae sensu Stevenson, widening the paleogeographical distribution of this subfamily.     

Endophytic fungi associated with leaves of Betulaceae in Japan

Diversity and species composition of endophytic fungi on leaves of 11 tree species in Betulaceae were studied, with reference to climatic, tree species, and seasonal variations. A total of 186 fungal isolates were obtained from 190 leaves collected in a subalpine forest, a cool temperate forest, and a subtropical forest in Japan, and were divided into 46 operational taxonomic units (OTUs) according to the base sequences of D1-D2 region of large subunit rDNA. The 2 most frequent OTUs were Muscodor sp. and Nemania sp. in Xylariaceae, followed by Gnomonia sp., Glomerella acutata , Apiosporopsis sp., Asteroma sp., and Cladosporium cladosporioides . The similarities of OTU composition in endophytic fungal assemblages on leaves of Betulaceae were generally low among the forests of different climatic regions. Fungal OTU compositions were relatively similar between 2 Betula species in the subalpine forest, whereas 7 tree species in the cool temperate forest were divided into 3 groups according to the similarity of endophytic fungal assemblages on the leaves, with 4 Carpinus species assigned into 2 of the 3 groups. The similarity of endophytic fungal assemblages between August and October was relatively high in the subalpine forest, whereas the seasonal changes were generally greater (i.e., the similarities among sampling dates were lower) in the cool temperate forest.