Comparative Leaf Anatomy of Nymphaeaceae (s. l.)

Leaf anatomy of six genera was investigated. The petiole of Brasenia schreberi possesses a pair of bundles, the other five possess closed, scattered vascular bundles, resembling those of the Monocotyledons. True vessels are absent. Air passages are present in the ground tissue of the petiole except for Nuphar pumilum. Leaves are all dorsiventral. Stomatal apparatuses of the Ranunculaceous type are generally confined to the upper surface of the lamina, but fewer stomata are found on the lower surface of the lamina of Nelumbo nucifera. The stomatal apparatuses of Nelumbo nucifera are of the Haplocheilic type in development, but of the Ranunculaceous type at maturity. Hydathodes and sclerenchymatous idioblasts are present only in Nelumbo nucifera. Glandular hairs and hydropotens occur on the lower surface of the lamina in all the investigated species except Nelumbo nucifera. Astrosclereids are present in all the taxa except Brasenia schreberi and Nelumbo nucifera. According to observations we consider that the genus Brasenia is a primitive one in Nymphaeaceae and it has a close phylogenetic relationship with Cabomba. They may be treated as an independent family, Cabombaceae, which is better included in the order Nymphaeales. Nymphaea, Nuphar, Euryale and Victoria are closely related to one another and should be retained in the family Nymphaeaceae. Nelumbo shows, specialized features distinct from those of the rest of the Nymphaeaceae. It should be segregatednot only as a distinct family but also as a distinct order, Nelumboales.     

Xylem of early angiosperms: Novel microstructure in stem tracheids of Barclaya (Nymphaeaceae)

Pit membranes of stem tracheids of all recognized species of Barclaya, an Indomalaysian genus of Nymphaeaceae, were studied with scanning electron microscopy (SEM). Pit membranes of the tracheids are composed of two thick layers, both constructed of fibrils much larger than those of tracheary elements of angiosperms other than Nymphaeaceae. The outer (distal) layer, which comprises the continuous primary wall around the tracheids, is spongiform, perforated by porosities of relatively uniform size, and confined to or most prominent on end walls of stem tracheids. The second layer consists of thick widely spaced fibrils that are oriented axially and are laid down proximally (facing the cell lumen) to the first (outer) layer, although continuous with it. These axial fibrils are attached at their ends to the pit cavities. This peculiar microstructure is not known outside Nymphaeaceae except in Brasenia and Cabomba (Cabombaceae, Nymphaeales), and has not been previously described for Barclaya. The longitudinally oriented threads and strands in perforation plates of secondary xylem of wood and stems of a variety of primitive woody angiosperms (e.g., Illicium) are not homologous to the pit membrane structure observed in stem tracheids of Barclaya, which, like other Nymphaeaceae, has only primary xylem and no perforation plates. The tracheid microstructure reported here is different from pit structures observed in any other group of vascular plants, living or fossil. The tracheid stem microstructures of Barclaya and other Nymphaeaceae appear to be a synapomorphy of Nymphaeaceae and Cabombaceae, and need further study with respect to ultrastructure and function.     

睡莲科的属间关系研究

本文用谱系分支法分析睡莲科的属间关系,３５个衍征中,分析了３１个特征的进化趋势,根据分析将睡莲科提升为睡莲目,分为３个科,莲科、水盾草科、睡莲科。     

睡莲科的核型分析及其分类学位置的探讨

本文对睡莲科6属6种代表植物的核型进行了研究,并探讨了它的分类学位置。结果如下：莲2n＝16=9sm+4m+3st;王莲2n＝24=8sm+8m+8T,蓝睡莲2n＝28,可配成14对,染色体小,第l号染色体上有2条随体;萍蓬草2n＝34＝18m+16sm;芡实2n=58,可配成29对,染色体小,第l号染色体有2条随体,莼菜2n＝72,可配成36对,染色体按大小可分成大,中、小三个类别。除莲外,其它5种植物的核型为首次报道。莼菜的体细胞染色体数目2n＝72和国外报道的2n＝80不相一致。莲的染色体以及形态学特征和其它睡莲科分类群显著不同,可将其从睡莲科中独立出来,并成立莲科和莲目。原归属于睡莲科的分类群仍组成睡莲目,并分别置于莼菜科和睡莲科。     

Phylogeny and divergence of basal angiosperms inferred from<Emphasis Type="Italic"> APETALA3</Emphasis>- and<Emphasis Type="Italic"> PISTILLATA</Emphasis>-like MADS-box genes

The B-class MADS-box genes composed of APETALA3 (AP3) and PISTILLATA (PI) lineages play an important role in petal and stamen identity in previously studied flowering plants. We investigated the diversification of the AP3-like and PI-like MADS-box genes of eight species in five basal angiosperm families: Amborella trichopoda (Amborellaceae); Brasenia schreberi and Cabomba caroliniana (Cabombaceae); Euryale ferox, Nuphar japonicum, and Nymphaea tetragona (Nymphaeaceae); Illicium anisatum (Illiciaceae); and Kadsura japonica (Schisandraceae). Sequence analysis showed that a four amino acid deletion in the K domain, which was found in all previously reported angiosperm PI genes, exists in a PI homologue of Schisandraceae, but not in six PI homologues of the Amborellaceae, Cabombaceae, and Nymphaeaceae, suggesting that the Amborellaceae, Cabombaceae, and Nymphaeaceae are basalmost lineages in angiosperms. The results of molecular phylogenetic analyses were not inconsistent with this hypothesis. The AP3 and PI homologues from Amborella share a sequence of five amino acids in the 5 region of exon 7. Using the linearized tree and likelihood methods, the divergence time between the AP3 and PI lineages was estimated as somewhere between immediately after to several tens of millions of years after the split between angiosperms and extant gymnosperms. Estimates of the age of the most recent common ancestor of all extant angiosperms range from ~140–210 Ma, depending on the trees used and assumptions made.     

睡莲科三属植物叶的比较解剖学研究

报道了睡莲科的睡莲属、莼菜属和萍蓬草属三属植物叶的比较解剖学特征。结果表明,莼菜属叶柄仅具一个维管束,其余二个属均有数个维管束,且维管束为有限的、星散排列,这一特征与单子叶植物的很相似;叶柄基本组织中,除萍蓬草属无气道外,其它两个属均有气道;在睡莲属和萍蓬草属中存在星状石细胞,而莼菜属中则无此细胞;莼菜属和萍蓬草属具腺毛,睡莲属无腺毛。由于睡莲科此三属植物叶的解剖学特点存在很大的差异,因此认为睡莲科的这三属可能来源于不同的祖先,因此建议将莼菜属和萍蓬草属从睡莲科中分离出来。分别独立为莼菜科和萍蓬草科。     

Phylogenetic systematics of the nymphaeales

A cladistic analysis was applied to reveal the phylogenetic relationships among the Nymphaeales. Seventeen out of twenty three characters in gross morphology, anatomy and palynology were analyzed, for their evolutionary polarities. From the results of the present analysis, the phylogenetic status of each genus and their relationships were clarified: 1)Nelumbo is a distinct taxon and is presumed to have originated from an ancestral stock of the Nymphaeales; 2)Ceratophyllum has a close phylogenetic relationship withCabomba; and 3) in the Nymphaeaceaesensu stricto, Nuphar and the remaining genral constitute a monophyletic group. A conclusion obtained from the present analysis was that the following three families should be recognized in the Nymphaeales; Nelumbonaceae Nymphaeaceae, and Ceratophyllaceae. The generaBrasenia andCabomba are traditionally classified in the Nymphaeaceae or in the independent family Cabombaceae. However, they should be included in the family Ceratophyllaceae.     

FRUITS AND SEEDS OF TRIBE GORDONIEAE (THEACEAE) FROM THE EOCENE OF NORTH AMERICA

A new genus and species Gordoniopsis polysperma and two new species of Gordonia (Gordonieae, Camellioideae, Theaceae) are described based on fossil fruit and seed remains. These specimens are part of a large flora consisting of various plant organs from the middle Eocene Claiborne Formation in western Kentucky and Tennessee. Gordoniopsis is a five-valved loculicidally dehiscent capsule similar to capsules of Gordonia but differing in having unwinged seeds and a greater number of seeds per locule. The two Gordonia species are among the earliest unequivocal records of the genus and two of only four fossil Gordonia species known with in situ seeds. Two extinct genera, Gordoniopsis and Andrewsiocarpon, and the extant genus Gordonia in the tribe Gordonieae are known from the middle Eocene Claiborne flora, suggesting an early radiation within the tribe. Based on a survey of Recent fruits and seeds we concur with Keng's proposal to merge Laplacea with Gordonia.     

Genetic diversity and population structure of Nuphar submersa (Nymphaeaceae), a critically endangered aquatic plant endemic to Japan,and implications for its conservation

Journal of Plant Research - Nuphar submersa (Nymphaeaceae) is a critically endangered freshwater macrophyte indigenous to central Japan, with only four small extant populations represented across...     

Paleogene fossil fruits of Stephania (Menispermaceae) from North America and East Asia

Stephania Loureiro is a large genus within Menispermaceae, with approximately 60 extant species naturally distributed in tropical to subtropical areas in Asia and Africa, and a few in Oceania. This genus possesses highly characteristic endocarps that facilitate identification of extant and fossil specimens. Here, we report some well-preserved fossil fruits of Stephania from North America and East Asia. The specimens indicate the endocarps were bony or woody with an obovate to obovate-rotund outline and a horseshoe-shaped locule. The endocarp length varies from 4.7 to 8.3 mm, and width from 3.7 to 7.0 mm. The endocarp has a clear foramen in the central area and is surrounded by a keel with ribs running along the dorsal surface. Only one lateral crest develops on each side of the endocarp. Two new species are recognized: Stephania wilfii Han & Manchester sp. nov. from the Paleocene to Eocene of Wyoming (USA), and Stephania jacquesii Han & Manchester sp. nov. disjunct between the late Eocene of Oregon (USA) and the late Oligocene of Guangxi Province (China). In addition, on the basis of more detailed morphological comparative analyses, we transfer the fossils formerly treated as Diploclisia auriformis (Hollick) Manchester from the early Eocene of London Clay, and the middle Eocene of Alaska and Oregon to Stephania auriformis (Hollick) Han & Manchester comb. nov. These fossil materials indicate a broader biogeographic distribution for the ancestors of extant Stephania lineages. This finding enhances our knowledge of the taxonomic and morphological diversity of Stephania and provides new evidence concerning its phytogeographic history.     

Do tracheid microstructure and the presence of minute crystals link Nymphaeaceae,Cabombaceae and Hydatellaceae?

Original scanning electron microscopy (SEM) observations are presented for stems of Brasenia schreberi and Cabomba caroliniana of Cabombaceae and three species of Trithuria of Hydatellaceae. End walls of stem tracheids of Brasenia have the same peculiar microstructure that we have reported in Barclaya, Euryale, Nuphar, Nymphaea (including Ondinea) and Victoria of Nymphaeaceae. This feature unites Cabombaceae with Nymphaeaceae. The minute rhomboidal crystals on the surfaces of stellate parenchyma cells of Brasenia reported by Solereder (1906. Oxford: University Press), but not noticed since, are figured. They are like the minute crystals of the often‐mentioned astrosclereids of Nymphaeaceae. Neither of these two features has been observed in Hydatellaceae. If the absence of these two features can be confirmed, the reason may be more related to ecology, development, habit and anatomical organization than to degree of phylogenetic relationship as shown by molecular studies. Anatomical observations on the stem anatomy of Trithuria are offered on the basis of paraffin sections prepared for a paper by Cheadle & Kosakai (1975. American Journal of Botany 62: 1017–1026); that study is notable for a discrepancy between an illustration of a specialized vessel element on the one hand and tabular data indicating long scalariform perforation plates on the other. Long scalariform perforation plates are mostly found in scalariformly pitted vessels of monocots, whereas the tracheary elements of Trithuria mostly have helical or annular thickenings. We were unable to demonstrate the presence of vessels in Hydatellaceae. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 572–582.     

Phylogenetic analysis of Nymphaeales using fast-evolving and noncoding chloroplast markers

The Nymphaeales (water-lilies and relatives) represent one of the earliest branching lineages of angiosperms and comprise about 70 aquatic species. Here, we present a comprehensive study of phylogenetic relationships within the Nymphaeales from a dataset containing 24 representatives of the order, including all currently recognized genera and all subgenera of the genus Nymphaea , plus 5 outgroup taxa. Nine different regions of the chloroplast genome − comprising spacers, group II introns, a group I intron, and a protein coding gene − were analysed. This resulted in a character matrix of 6597 positions and an additional 369 characters obtained from coded length mutations. Maximum parsimony and Bayesian analyses of the complete dataset yielded congruent, fully resolved and well-supported trees. Our data confirm the monophyly of the Cabombaceae but do not provide convincing support for the monophyly of Nymphaeaceae with respect to Nuphar . Moreover, the genus Nymphaea is inferred to be paraphyletic with respect to Ondinea , Victoria and Euryale . In fact, the Australian endemic Ondinea forms a highly supported clade with members of the Australian Nymphaea subgenus Anecphya . In addition, Victoria and Euryale are inferred to be closely related to a clade comprising all night-blooming water-lilies ( Nymphaea subgenera Hydrocallis and Lotos ). An experimental approach showed taxon sampling to be of influence on the nodes reconstructed in core Nymphaeaceae. The results underscore that more diverse genera, if not clearly known to be monophyletic, should be represented by all major lineages.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 141–163.     

Pollen ontogeny in Brasenia (Cabombaceae, Nymphaeales)

Brasenia is a monotypic genus sporadically distributed throughout the Americas, Asia, Australia, and Africa. It is one of eight genera that comprise the two families of Nymphaeales, or water lilies: Cabombaceae (Brasenia, Cabomba) and Nymphaeaceae (Victoria, Euryale, Nymphaea, Ondinea, Barclaya, Nuphar). Evidence from a range of studies indicates that Nymphaeales are among the most primitive angiosperms. Despite their phylogenetic utility, pollen developmental characters are not well known in Brasenia. This paper is the first to describe the complete pollen developmental sequence in Brasenia schreberi. Anthers at the microspore mother cell, tetrad, free microspore, and mature pollen grain stages were studied using combined scanning electron, transmission electron, and light microscopy. Both tetragonal and decussate tetrads have been identified in Brasenia, indicating successive microsporogenesis. The exine is tectate-columellate. The tetrad stage proceeds rapidly, and the infratectal columellae are the first exine elements to form. Development of the tectum and the foot layer is initiated later during the tetrad stage, with the tectum forming discontinuously. The endexine lamellae form during the free microspore stage, and their development varies in the apertural and non-apertural regions of the pollen wall. Degradation of the secretory tapetum also occurs during the free microspore stage. Unlike other water lilies, Brasenia is wind-pollinated, and several pollen characters appear to be correlated with this pollination syndrome. The adaptive significance of these characters, in contrast to those of the fly-pollinated genus Cabomba, has been considered. Brasenia does not produce pollenkitt nor develop tectal microchannels as does Cabomba. Instead, the discontinuity of the tectum reduces the amount of sporopollenin in the wall, which may allow for more effective wind dispersal. The importance of reassessing palynological characters in light of new ontogenetic data and the phylogenetic implications of this reevaluation are also discussed.     

Gingkos and multituberculates: evolutionary interactions in the tertiary

The genus Ginkgo is a north temperate gymnosperm taxon represented by fossilized leaves and wood from the early Jurassic through the Pliocene, and by the living species G. biloba native to eastern China. Seeds produced by this widely cultivated tree consist of an odoriferous, vesicatory coat surrounding a hard-shelled "nut." Dispersal of ginkgo seeds is a two step process: repulsion of predators by the toxic coat, followed by attraction of dispersers by the edible "nut." Based on anatomical and distributional evidence, extinct mammalian multituberculates in the genus Ptilodus are plausible consumers and dispersers of ginkgo seeds during the Paleocene and the Eocene. From the Oligocene through Pleistocene, seed-caching rodents are the most likely dispersal agents of ginkgo. Among extant genera in the class Coniferopsida which produce fleshy, animal-dispersed seeds, there appear to be two distinct evolutionary lines: (1) those with relatively large (greater than 20 mm), odoriferous diaspores dispersed primarily by mammals; and (2) those with relatively small (less than 10 mm), visually attractive diaspores dispersed primarily by birds.     

Gynoecium diversity and systematics of the paleoherbs

Gynoecium and ovule structure was compared in representatives of all families of the paleoherbs, including Nymphaeales (Cabombaceae, Nymphaeaceae), Piperales (Saururaceae, Piperaceae), Aristolochiales (Lactoridaceae, Aristolochiaceae), Rafflesiales (Hydnoraceae, Rafflesiaceae) and, in addition, Ceratophyllaceae and Nelumbonaceae, both of which were earlier included in Nymphaeales, but then segregated and with an unestablished position. In all representatives studied, the carpels are closed at anthesis. Carpel closure is attained in three different ways: (1) postgenital fusion of inner surfaces (Piperales, Aristolochiales); (2) occlusion by secretion or mutual appression of inner surfaces without postgenital fusion (Cabombaceae, Ceratophyllaceae, Nelumbonaceae (?) or (3) strong secretion combined with postgenital fusion at the periphery of the carpel (Nymphaeaceae). In Cytinus (Rafflesiaceae), after an earlier developmental stage with apparent postgenital fusion there is strong internal secretion (within the cell walls). Stigma shape tends to be double-crested in the basal taxa of each order: Cabombaceae (Brasenia), Saururaceae, and Lactoridaceae. In some Aristolochiaceae and Cytinus (Rafflesiaceae) they have two lobes in the transverse symmetry plane (i. e. at right angles to the median plane) or, if the carpels are united, the stigmatic lobes are commissural, accordingly. Stigmas are unicellular papillate and secretory in most taxa, but the papillae are uniseriate-pluricellular in some (not basal) Nymphaeaceae, Asaroideae (Aristolochiaceae) and Cytinus (Rafflesiaceae). Ceratophyllaceae have smooth stigmas. Intrusive oil cells in the carpel epidermis were found in Piperales and Aristolochiaceae. Mature ovules vary in length between 0. 2 mm and 2. 5 mm. Mature nucelli vary in breadth between 0. 03 mm and 1. 6 mm. These differences are larger than in the other major magnoliid groups. The outer integument is fully annular (not semiannular) in all taxa with orthotropous ovules (all Piperales and Barclaya of Nymphaeaceae) and also in some with anatropous ovules (some Nymphaeaceae, some Aristolochiaceae). The integuments are variously lobed or unlobed; both integuments tend to exhibit the same behaviour within a family, either both lobed or both unlobed. The results strongly support three pairs of families in sister group relationships, as suggested by studies based on other characters: Cabombaceae-Nymphaeaceae, Saururaceae-Piperaceae, and Lactoridaceae-Aristolochiaceae, and Hydnoraceae-Rafflesiaceae to some extent. Piperales and Aristolochiales are closer to each other than either is to Nymphaeales. Nelumbonaceae is isolated, as is Ceratophyllaceae, but the status of the latter is more difficult to interpret owing to apparent reduction in morphological, anatomical and histological traits.     

Beardia vancouverensis gen. et sp. nov. (Juglandaceae): permineralized fruits from the Eocene of British Columbia

Large numbers of permineralized juglandaceous fruits were identified in calcareous nodules from the Eocene Appian Way locality on Vancouver Island, British Columbia, Canada. The fruits, small dorsiventrally flattened nutlets, 4.5-7.0 mm long and 5.5-9.0 × 3-5 mm in diameter, were studied using cellulose acetate peels. They are wingless, ribbed, and have a lobed epicarp that surrounds the nutlet. Cells of the inner epicarp are thin-walled and traversed by a system of branching vascular strands. The stony nutlet wall is composed of fibers, with an outer layer of distinctive idioblasts. The fruits have a symmetry like that in Juglandaceae, subfamily Juglandoideae, tribe Platycaryeae, while the fibrous nut walls are like those of subfamily Engelhardioideae. This unique combination of characters indicates that these fruits represent a new genus and species of Juglandaceae: Beardia vancouverensis gen. et sp. nov. The excellent preservation of the Appian Way specimens has allowed a unique view of the internal fruit anatomy and external morphology. As the only wingless, flattened nuts known in the family, they further extend the range of morphological variation in fruits in the family. These fossils further support the hypothesis that North America was an important center of generic diversity for Juglandaceae during the early Tertiary.     

Recent and Tertiary Seeds of the Nymphaeaceae sensu lato with a Revision of Brasenia ovula (Brong.) Reid and Chandler

The nine extant genera within the Nymphaeaceae s l (Water Lilies)are shown to be separable from one another on the basis of seedmorphology In particular, epidermal detail, vertical sectionof the testa and relative position of the micropyle and hilumare diagnostic for each genus These features are consideredin connection with current systematic treatments of this familyFossil seeds are reviewed at the generic level and many of theseeds previously assigned to Brasenia ovula (Brong ) Reid andChandler are shown to belong to an extinct genus of Nymphaeaceaeintermediate between the currently accepted families Cabombacaceaeand Nymphaeaceae s s They are redescribed as Sabrenia chandleraegen et sp nov. The British Tertiary fossils Brasenia spinosaChandler, Palaeonymphaea eocenica Chandler emend and ?Nymphaealiminis sp nov are described Fossil material of Carpolithesovulum Brongniart 1822a, Brasenia victoria (Casp ) Weberbauer1893, B teumeri Kirchheimer 1935, B tenuicostata Nikitin 1965and Nymphaea arethusae Grambast 1962 has been studied for comparativepurposes The use of ‘?’ before the extant genericname is advocated when all features of a fossil indicate thatit may be placed in a living genus but when certain additional,critical features of the living genus are lacking on the fossil. Nymphaeaceae, water lilies, seeds, palaeobotany, Tertiary, Sabrenia chandlerae gen et sp nov Nymphaea liminis sp nov, Brasenia ovula     

Remarkably preserved annelid worms from the La Meseta Formation (Eocene), Seymour Island, Antarctica

Abstract: Worm tubes, which exhibit the replaced tube-lining membrane, have been collected from the lowermost Lower Eocene Acantilados Allomember of the La Meseta Formation, Seymour Island, Antarctica. The discovery represents the oldest examples of preservation of the tube-lining membrane of tube-dwelling Polychaeta in the fossil record. A new genus and species, Caprascolex antarcticus , are described. The specimens are preserved as thin coatings of amorphous iron oxide on the inner surface of the moulds interpreted to be the replaced tube-lining membrane. Examination of the rarely described tube-lining mucosoid membrane in extant polychaetes shows that the fossils are nearly identical in morphology and scale to extant forms. These fossils record in remarkable detail the morphology of the tube-lining membrane, which appears to be composed of growth bands formed as the worm constructed the tube. The tube-lining is believed to have been originally preserved as pyrite, with subsequent oxidation to iron oxide. The tube-lining membrane of worm tubes possibly is known from only one other fossil occurrence.