Evolution of fruit types and seed dispersal:A phylogenetic and ecological snapshot

Success of flowering plants is greatly dependent on effective seed dispersal. Specific fruit types aid different mechanisms of seed dispersal. However, little is known about what evolutionary forces have driven the diversification of fruit types and whether there were phylogenetic constraints on fruit evolution among angio-sperm lineages. To address these questions, we first surveyed the orders and families of angiosperms for fruit types and found no clear association between fruit types and major angiosperm lineages, suggesting there was little phylogenetic constraint on fruit evolution at this level. We then surveyed fruit types found in two contrasting habitats: an open habitat including the Indian desert and North American plains and prairies, and a closed forest habitat of Australian tropical forest. The majority of genera in the survey of tropical forests in Australia were fleshy fruit trees, whereas the majority of genera in the survey of prairies and plains in central North America were herbs with capsules and achenes. Both capsules and achenes are frequently dispersed by wind in the open, arid habitat, whereas fleshy fruits are generally dispersed by animals. Since desert and plains tend to provide continuous wind to aid dispersal and there are more abundant mammal and bird dispersers in the closed forest, this survey suggests that fruit evolution was driven at least in part by dispersal agents abundant in particular habitats.     

果实类型和种子传播的进化:系统发育和生态学简论

Success of flowering plants is greatly dependent on effective seed dispersal. Specific fruit types aid different mechanisms of seed dispersal. However, little is known about what evolutionary forces have driven the diversification of fruit types and whether there were phylogenetic constraints on fruit evolution among angiosperm lineages. To address these questions, we first surveyed the orders and families of angiosperms for fruit types and found no clear association between fruit types and major angiosperm lineages, suggesting there was little phylogenetic constraint on fruit evolution at this level. We then surveyed fruit types found in two contrasting habitats an open habitat including the Indian desert and North American plains and prairies, and a closed forest habitat of Australian tropical forest. The majority of genera in the survey of tropical forests in Australia were fleshy fruit trees, whereas the majority of genera in the survey of prairies and plains in central North America were herbs with capsules and achenes. Both capsules and achenes are frequently dispersed by wind in the open, arid habitat, whereas fleshy fruits are generally dispersed by animals. Since desert and plains tend to provide continuous wind to aid dispersal and there are more abundant mammal and bird dispersers in the closed forest, this survey suggests that fruit evolution was driven at least in part by dispersal agents abundant in particular habitats.     

Biogeography of seed-dispersal syndromes, life-forms and seed sizes among woody rain-forest plants in Australia's subtropics

Aim To enhance our understanding of the evolutionary interactions between seed‐dispersal syndromes, life‐forms, seed size, and habitat characteristics by studying their association with the regional‐scale distributions of subtropical rain‐forest plants in the context of climatic gradients. Location South‐east Queensland, subtropical eastern Australia (152° E, 26° S). Methods We classified 250 rain‐forest sites into six floristic site‐groups based on their woody plant composition. The resulting classification was strongly associated with variation in rainfall. The distribution of species across the floristic site‐groups was used to assign 568 species to seven habitat classes (one class for ‘widespread’ species, with all other species classified according to the site‐group within which they were most frequent). Species were also classified for three other categorical life‐history factors: three dispersal syndromes based on diaspore morphology (fleshy, wind‐assisted, and unadorned); four life‐forms (trees, shrubs and small trees, tall climbers, and short and shrubby climbers); and four seed‐diameter classes (< 3 mm, ≥ 3 and < 4.5 mm, ≥ 4.5 and < 7 mm, and ≥ 7 mm). We used a basic comparative approach augmented by simple phylogenetically constrained comparisons to assess association between dispersal syndrome, seed size, life‐form, and habitat class. Results Across the rain forests of south‐east Queensland, the proportion of species with fleshy diaspores or of large stature increases with rainfall. High‐rainfall sites also have larger average seed sizes, but the difference in average seed size between high‐ and low‐rainfall sites is small compared with variation within sites. Among species, those with fleshy fruit tend to have larger seeds and to favour high‐rainfall sites. Very few small trees produce diaspores adapted for wind‐assisted dispersal. On average, species with unadorned diaspores have smaller seeds than those with fleshy diaspores. However, within sites, species with unadorned and fleshy diaspores have similar average seed sizes, and some species with unadorned diaspores from high‐rainfall habitats have extremely large seeds. Main conclusions Commonly observed associations between fleshy fruit, larger plants, larger seeds, and productive habitats are apparent within the rain‐forest flora of south‐east Queensland. However, these associations are generally weak and involve complex interactions. For example, the strong tendency for species with fleshy fruit to have larger seeds than those with unadorned diaspores concealed a significant group of species from wetter forests that produce extremely large seeds and unadorned diaspores. The most widespread species in this study tend to be large plants (particularly robust lianes) and to produce fleshy fruit, but they tend not to have relatively large seeds. The association between large seeds, large plants, fleshy fruit and productive habitats is discussed as part of an evolutionary strategy favouring fitness in populations close to carrying capacity. We review some problems with focusing on establishment chances per seed as the driver towards association between large seeds, large plants and productive rain‐forest habitats (the difficult‐establishment hypothesis). Instead we suggest that production of large, short‐lived seeds by long‐lived plants in temporally stable, closed habitats may reflect the limited evolutionary potential for strategies enhancing colonization (e.g. producing large numbers of dormant seeds), thus allowing the establishment benefits of large seeds greater selective influence (the slow‐replacement hypothesis). The association of fleshy fruit with large seeds probably reflects the difficulty of dispersing large seeds by other means (the difficult‐dispersal hypothesis).     

Extended phylogeny of Aquilegia: the biogeographical and ecological patterns of two simultaneous but contrasting radiations

Studies of the North American columbines (Aquilegia, Ranunculaceae) have supported the view that adaptive radiations in animal-pollinated plants proceed through pollinator specialisation and floral differentiation. However, although the diversity of pollinators and floral morphology is much lower in Europe and Asia than in North America, the number of columbine species is similar in the three continents. This supports the hypothesis that habitat and pollinator specialisation have contributed differently to the radiation of columbines in different continents. To establish the basic background to test this hypothesis, we expanded the molecular phylogeny of the genus to include a representative set of species from each continent. Our results suggest that the diversity of the genus is the result of two independent events of radiation, one involving Asiatic and North American species and the other involving Asiatic and European species. The ancestors of both lineages probably occupied the mountains of south-central Siberia. North American and European columbines are monophyletic within their respective lineages. The genus originated between 6.18 and 6.57 million years (Myr) ago, with the main pulses of diversification starting around 3 Myr ago both in Europe (1.25–3.96 Myr ago) and North America (1.42–5.01 Myr ago). The type of habitat occupied shifted more often in the Euroasiatic lineage, while pollination vectors shifted more often in the Asiatic-North American lineage. Moreover, while allopatric speciation predominated in the European lineage, sympatric speciation acted in the North American one. In conclusion, the radiation of columbines in Europe and North America involved similar rates of diversification and took place simultaneously and independently. However, the ecological drivers of radiation were different: geographic isolation and shifts in habitat use were more important in Europe while reproductive isolation linked to shifts in pollinator specialisation additionally acted in North America.     

Integrated Fossil and Molecular Data Reveal the Biogeographic Diversification of the Eastern Asian-Eastern North American Disjunct Hickory Genus (Carya Nutt.)

The hickory genus (Carya) contains ca. 17 species distributed in subtropical and tropical regions of eastern Asia and subtropical to temperate regions of eastern North America. Previously, the phylogenetic relationships between eastern Asian and eastern North American species of Carya were not fully confirmed even with an extensive sampling, biogeographic and diversification patterns had thus never been investigated in a phylogenetic context. We sampled 17 species of Carya and 15 species representing all other genera of the Juglandaceae as outgroups, with eight nuclear and plastid loci to reconstruct the phylogeny of Carya. The phylogenetic positions of seven extinct genera of the Juglandaceae were inferred using morphological characters and the molecular phylogeny as a backbone constraint. Divergence times within Carya were estimated with relaxed Bayesian dating. Biogeographic analyses were performed in DIVA and LAGRANGE. Diversification rates were inferred by LASER and APE packages. Our results support two major clades within Carya, corresponding to the lineages of eastern Asia and eastern North America. The split between the two disjunct clades is estimated to be 21.58 (95% HPD 11.07-35.51) Ma. Genus-level DIVA and LAGRANGE analyses incorporating both extant and extinct genera of the Juglandaceae suggested that Carya originated in North America, and migrated to Eurasia during the early Tertiary via the North Atlantic land bridge. Fragmentation of the distribution caused by global cooling in the late Tertiary resulted in the current disjunction. The diversification rate of hickories in eastern North America appeared to be higher than that in eastern Asia, which is ascribed to greater ecological opportunities, key morphological innovations, and polyploidy.     

On the Distribution and Origin of Salix in the World

1. The distribution of Salix species among the continents. There are about 526 species of Salix in the world, most of which are distributed in the Northern Hemisphere with only a few species in the Southern Hemisphere. In Asia, there are about 375 species, making up 71.29 percent of the total in the world, including 328 endemics; in Europe, about 114 species, 21.67 percent with 73 endemics; in North America, about 91 species, 17.3 percent with 71 endemics; in Africa, about 8 species, 1.5 percent, with 6 endemics. Only one species occurs in South America. Asia, Europe and North America have 8 species in common (excluding 4 cultivated species). There are 34 common species between Asia and Europe, 14 both between Europe and North America and between Asia and North America, 2 between Asia and Africa. Acording to the Continental Drift Theory, the natural circumstances which promoted speciation and protected newly originated and old species were created by the orogenic movement of the Himalayas in the middle and late Tertiary. Besides, the air temperature was a little higher in Asia than in Europe and North America (except its west part) and the dominant glaciers were mountainous in Asia during the glacial epoch in the Quaternary Period. Then willows of Europe moved southwards to Asia. During the interglacial period they moved in opposite direction. Such a to-and-fro willow migration between Asia and Europe and between and North America occurred so often that it resulted in the diversity of willow species in Asia. Those species of willows common among the continents belong to the Arctic flora. 2. The multistaminal willows are of the primitive group in Salix. Asia has 28 species of multistaminal willows, but Europe has only one which is also found in Asia. These 28 species are divided into two groups, “northern type” and “southern type”, according to morphology of the ovary. The boundary between the two forms in distribution is at 40°N. The multistaminal willows from south Asia, Africa and South America are very similar to each other and may have mutually communicated between these continents in the Middle or Late Cretaceous Period. The southern type willows in south Asia are similar to the North American multistaminal willows but a few species. The Asian southern type willows spreaded all over the continents of Europe, Asia and North America through the communication between them before the Quaternany Period. Nevertheless, it is possible that the willows growing in North America immigranted through the middle America from South America. The Asian northern type multistaminal willows may have originated during the ice period. The multistaminal willows are more closed to populars in features of sexual organs. They are more primitive than the willows with 1-3 stamens and the most primitive ones in the genus. 3. The center of origin and development of willows Based on the above discussion it is reasonable to say that the region between 20°-40°N in East Asia is the center of the origin and differentiation of multistaminal willows. It covers Southern and Southwestern China and northern Indo-China Pennisula.     

Genetic diversity and population structure identify the potential source of the invasive red clover casebearer moth, <Emphasis Type="Italic">Coleophora deauratella</Emphasis>, in North America

The red clover casebearer, Coleophora deauratella, is an invasive pest of red clover grown for seed in North America. In 2006, an outbreak in Alberta, Canada was discovered that resulted in significant seed losses, while further invasion threatens the world’s largest red clover forage seed production region in Oregon, USA. Prior to the recent outbreak, C. deauratella was thought to be restricted to eastern North America in its invasive range. We sequenced a 615-bp fragment of the mitochondrial cytochrome c oxidase subunit 1 gene, and developed three microsatellite markers to assess the genetic diversity and population structure of C. deauratella in North America and its native range in Europe. We observed signatures of a founder effect in North American populations and a further loss of genetic diversity within Alberta populations. Most genetic differentiation was found between continents, with no evidence of isolation-by-distance within each continent. From the limited number of European populations sampled, a single introduction from Switzerland is the most probable source of North American populations based on similar mitochondrial diversity and lack of population differentiation. Within North America, based on increased genetic diversity compared to the rest of the continent, the first North American record from Ithaca, NY, and the first documented outbreak in southern Ontario in 1989, the initial C. deauratella invasion most likely occurred in southern Ontario, Canada or adjacent states in the USA, followed by transport throughout the continent. This study provides insight into the phylogeographic history of C. deauratella in North America and Europe and may help to identify a regional source of future classical biological control agents.     

Species richness in plant genera disjunct between temperate eastern Asia and North America

The species richness of 109 amphi-Pacific disjunct genera was examined in eastern Asia and North America. Although the entire flora of eastern Asia contains approximately one-third more species than that of North America, the difference in species richness among disjunct taxa is less. When woody and herbaceous genera are considered separately, the former exhibit a strong diversity bias favouring eastern Asia whereas there is no significant difference in diversity between continents among herbaceous genera. This result is not due to habitat differences between woody and herbaceous genera, because the disjunct herbs inhabit primarily moist forests and woodlands. This result is also not related to relative phylogenetic advancement, even though older major lineages of plants tend to have a predominance of woody taxa. Woody genera are distributed in lower latitudes than herbaceous genera on both continents, and both woody and herbaceous genera are distributed in lower latitudes in eastern Asia than in North America. The North American temperate flora is primarily a relict of a flora form 7 more widespread throughout the Northern Hemisphere. Contemporary patterns of diversity suggest that the effects of climate changes in the late Tertiary were less severe in eastern Asia and promoted diversification, but were more severe in North America and may have caused widespread extinction. The difference in the effect of climate change on diversity in herbaceous and woody lineages reflects the different ecological relationships of species having these contrasting life forms. Clearly, the contemporary floras of eastern Asia and North America bear the imprint of history and emphasize the important interface between ecological relationships and evolutionary responses.     

Tetrahydrocannabinol levels in hemp (cannabis sativa) germplasm resources

In most of the western world where industrial hemp, Cannabis sativa, is licensed for cultivation, the plants must not exceed a level of 0.3% tetrahydrocannabinol (THC), the principal intoxicating constituent of the species. Because there are no publicly available germplasm hemp collections in North America and only a very few, recent North American cultivars have been bred, the future breeding of cultivars suitable for North America is heavily dependent on European cultivars and European germplasm collections. Based mostly on material from Europe, this study surveyed THC levels of 167 accessions grown in southern Ontario, making this the largest survey to date of germplasm intended for breeding in North America. Forty-three percent of these had THC levels ≥0.3% and, therefore, are unsuitable for hemp development in North America. Discrepancies were found between THC levels reported for some germplasm holdings in Europe when they were grown in Canada and, accordingly, verification of THC levels developed in North America is necessary.     

Some observations on shell-shape variation in North American populations of Nucella lapillus (L.)

This paper considers shell-shape variation in samples of the dog-whelk/dog-winkle, ucella lapillus , from the southern half of its North American range, between 41 and 46N, and compares it with the pattern seen in Europe. At the extreme southern limit of its American range, to the south of Cape Cod, the species exhibits features to be expected in an animal close to an environmental limit. It is generally rare and has a patchy distribution. There is little variation in the shell: almost all adult individuals have rather large, thick, white, elongated shells. This contrasts sharply with the situation in Portugal, at the southern limit in Europe, where the animals have small thin, coloured shells of intermediate shape.
Away from the marginal situation, north of Nahant (42^CN) in America, the species shows much the same range of variability in shell size, shape and colour on both sides of the Atlantic. Most populations appear to show the same pattern of shape variation in asociation with the exposure of their habitat to wave action. Animals from exposed sites tend to have shorter, squatter shells than their compatriots in shelter. However, in America as in some parts of Europe, there are occasional enclaves which do not fit the usual pattern. It is interesting to note that the form normally associated with extremely exposed shores from Brittany to Faroe in Europe is found in Atlantic Canada but is apparently absent from southern populations in both the U.S.A and the Iberian Peninsula.     

Putative source of the invasive Sirex noctilio fungal symbiont, Amylostereum areolatum, in the eastern United States and its association with native siricid woodwasps

Two genotypes of the fungal symbiont Amylostereum areolatum are associated with the invasive woodwasp Sirex noctilio first found in North America in 2004. S. noctilio is native to Europe but has been introduced to Australasia, South America and Africa where it has caused enormous losses in pine plantations. Based on nucleotide sequence data from the intergenic spacer region (IGS) of the nuclear ribosomal DNA, the A. areolatum genotypes found in North America are most similar to genotypes found in Europe, and not to genotypes from the southern hemisphere. Although two IGS strains of A. areolatum were found in North America it cannot be stated whether A. areolatum was introduced to North America from Europe once or twice based on our study. Genetic groupings formed by sequencing data were in most cases supported by vegetative compatibility groups (VCGs). Other siricid woodwasp species in the genus Sirex are native to North America. The North American native Sirex edwardsii emerging from the same tree as S. noctilio carried the same strain of A. areolatum as S. noctilio. The North American native Sirex sp. ‘nitidus’ collected outside the geographical range of S. noctilio carried a unique strain within A. areolatum. Our findings of A. areolatum in the native North American species, S. sp. ‘nitidus’, contrast with the previous view that A. areolatum was not present in North America before the accidental invasion of S. noctilio.     

Habitat partitioning in European and North American pond-breeding frogs and toads

Abstract. Distributions of species along a freshwater habitat gradient, ranging from ephemeral pools with few predators to permanent lakes with fish, have been used to infer how predation establishes trade-offs that promote ecological specialization. Larval anurans are said to support the trade-off model, but there are few comparable and quantitative habitat data available to assess this claim. I performed a survey of field biologists to evaluate the habitats of similar sets of species in the northern parts of Europe (40 respondents and 12 species) and eastern North America (30 respondents and 8 species), using a standard set of criteria. For six European species I also had quantitative field sampling data, and found close agreement between survey results and predator densities experienced by tadpoles in the field. Distributions of most species were restricted to only part of the habitat gradient, as expected under the trade-off model. The survey confirmed reports that North Ameri-can Rana species replace one another along the gradient, but this was not true in Europe. European Rana were no different from the North American species in their seasonal and geographical overlap, so the absence of habitat partitioning in European Rana may result from interactions with other species or the special impact of glaciation in Europe. Habitats were unrelated to evolutionary relationships among species, suggesting that changes in habitat evolve quickly. The survey approach was useful for comparing distributions of species, and for generating hypotheses about evolutionary responses to habitat gradients.     

Phylogeny and taxonomy of the damselfly genus Enallagma and related taxa (Odonata: Zygoptera: Coenagrionidae)

Abstract The zygopteran genus Enallagma has been the subject of numerous behavioural and ecological studies, but phylogenetic relationships among species have been examined only within eastern North America, and even the composition and diagnosis of the genus are unclear on a world-wide basis. Most authorities currently recognize about seventy species within Enallagma , comprising two major radiations, in North America and Africa. This study, using morphological data, demonstrates that the North American and a few related Palaearctic species form a monophyletic group that is quite distinct from the African species. The latter are themselves divided into at least three, and probably four, separate clades, one of which may be related to E. parvum of India. Consequently, three of Kennedy's long disused genera, Africallagma , Amphiallagma and Proischnura ( Kennedy, 1920 ) are resurrected and two new genera, Azuragrion gen.n. and Pinheyagrion gen.n. are established for the remaining African taxa. Finally, Enallagma is divided into two subgenera, Enallagma s.s ., the typical 'bluets', including many North American, Holarctic and Palaearctic species, and Chromatallagma subgen.n., comprising a group of species of more variable colour that is confined to North America, the Caribbean and northernmost South America.     

New adapiform primate of Old World affinities from the Devil's Graveyard Formation of Texas

Most adapiform primates from North America are members of an endemic radiation of notharctines. North American notharctines flourished during the Early and early Middle Eocene, with only two genera persisting into the late Middle Eocene. Here we describe a new genus of adapiform primate from the Devil’s Graveyard Formation of Texas. Mescalerolemur horneri, gen. et sp. nov., is known only from the late Middle Eocene (Uintan) Purple Bench locality. Phylogenetic analyses reveal that Mescalerolemur is more closely related to Eurasian and African adapiforms than to North American notharctines. In this respect, M. horneri is similar to its sister taxon Mahgarita stevensi from the late Duchesnean of the Devil’s Graveyard Formation. The presence of both genera in the Big Bend region of Texas after notharctines had become locally extinct provides further evidence of faunal interchange between North America and East Asia during the middle Eocene. The fact that Mescalerolemur and Mahgarita are both unknown outside of Texas also supports prior hypotheses that low-latitude faunal assemblages in North America demonstrate increased endemism by the late middle Eocene.     

Taxonomic diversity of the terrestrial bird and mammal fauna in temperate and boreal biomes of the northern hemisphere

Abstract. Using comprehensive range information of northern Hemisphere birds and mammals, we assessed the taxonomic diversity of these two groups in four different regions: Europe, east Asia, and western and eastern North America. East Asia is the richest region in the number of bird and mammal species, genera, families and orders, except that mammal species richness is highest in western North America. Eastern North America is taxonomically the poorest region, but when only forest-associated taxa were considered in mammals taxonomic diversity is equally low in Europe and in eastern North America, and in birds, Europe is the least diverse region. Patterns in endemic taxa follow overall taxonomic diversity. The proportion of shared taxa between regions is higher among boreal species and genera than among all taxa. A comparison with tree species diversity underpins the role of east Asia as the most diverse of all northern biota. Largely congruent patterns at different taxonomic levels emphasizes the role of historical processes, such as differential extinction rate in response to paleoenvironmental fluctuations, in producing these patterns, but we stress the need for more research on the coevolution of species diversity and habitat diversity.     

Intercontinental dispersal of Typha angustifolia and T. latifolia between Europe and North America has implications for Typha invasions

The full effects of biological invasions may be underestimated in many areas because of cryptogenic species, which are those that can be identified as neither native nor introduced. In North America, the cattails Typha latifolia, T. angustifolia, and their hybrid T. × glauca are increasingly aggressive invaders of wetlands. There is a widespread belief that T. latifolia is native to North America and T. angustifolia was introduced from Europe, although there has so far been little empirical support for the latter claim. We used microsatellite data and chloroplast DNA sequences to compare T. latifolia and T. angustifolia genotypes from eastern North America and Europe. In both species, our data revealed a high level of genetic similarity between North American and European populations that is indicative of relatively recent intercontinental dispersal. More specifically, the most likely scenario suggested by Approximate Bayesian Computation was an introduction of T. angustifolia from Europe to North America. We discuss the potential importance of our findings in the context of hybridization, novel genomes, and increasingly invasive behaviour in North American Typha spp.     

Origin,Differentiation, and Geographic Distribution of the Chenopodiaceae

Numbers of species and genera,endemic genera,extant primitive genera,relationship and distribution patterns of presently living Chenopodiaceae(two subfamilies,12 tribes,and 118 genera)are analyzed and compared for eight distributional areas,namely central Asia,Europe,the Mediterranean region,Africa,North America,South America, Australia and East Asia． The Central Asia,where the number of genera and diversity of taxa are greater than in other areas,appears to be the center of distribution of extant Chenopodiaceae．North America and Australia are two secondary centers of distribution． Eurasia has 11 tribes out of the 12,a total of 70 genera of extant chenopodiaceous plants,and it contains the most primitive genera of every tribe． Archiatriplex of Atripliceae,Hablitzia of Hablitzeae,Corispermum of Corispermeae,Camphorosma of Camphorosmaea,Kalidium of Salicornieae,Polecnemum of Polycnemeae,Alexandra of Suaedeae,and Nanophyton of Salsoleae,are all found in Eurasia,The Beteae is an Eurasian endemic tribe,demonstrating the antiquity of the Chenopodiaceae flora of Eurasia．Hence,Eurasia is likely the place of origin of chenopodiaceous plants． The presence of chenopodiaceous plants is correlated with an arid climate．During the Cretaceous Period,most places of the continent of Eurasia were occupied by the ancient precursor to the Mediterranean,the Tethys Sea．At that time the area of the Tethys Sea had a dry and warm climate．Therefore,primitive Chenopodiaceae were likely present on the beaches of this ancient land．This arid climatic condition resulted in differentiation of the tribes Chenopodieae,Atripliceae,Comphorosmeae,Salicornieae,etc．,the main primitive tribes of the subfamily Cyclolobeae. Then following continental drift and the Laurasian and Gondwanan disintegration, the Chenopodiaceae were brought to every continent to propagate and develop, and experience the vicissitudes of climates, forming the main characteristics and distribution patterns of recent continental floras. The tribes Atripliceae, Chenopodieae, Camphorosmeae, and Salicornieae of recent Chenopodiaceae in Eurasia, North America, South America, southern Africa, and Australia all became strongly differentiated. However, Australia and South America, have no genera of Spirolobeae except for a few maritime Suaeda species. The Salsoleae and Suaedeae have not arrived in Australia and South America, which indicates that the subfamily Spirolobeae developed in Eurasia after Australia separated from the ancient South America-Africa continent, and South America had left Africa. The endemic tribe of North America, the tribe Sarcobateae, has a origin different from the tribes Salsoleae and Suaedeae of the subfamily Spirolobeae. Sarcobateae flowers diverged into unisexuality and absence of bractlets. Clearly they originated in North America after North America had left the Eurasian continent. North America and southern Africa have a few species of Salsola, but none of them have become very much differentiated or developed, so they must have arrived through overland migration across ancient continental connections. India has no southern African Chenopodiaceae floristic components except for a few maritime taxa, which shows that when the Indian subcontinent left Africa in the Triassic period, the Chenopodiaceae had not yet developed in Africa. Therefore, the early Cretaceous Period about 120 million years ago, when the ancient Gondwanan and Laurasian continents disintegrated, could have been the time of origin of Chenopodiaceae plants.The Chinese flora of Chenopodiaceae is a part of Chenopodiaceae flora of central Asia. Cornulaca alaschnica was discovered from Gansu, China, showing that the Chinese Chenopodiaceae flora certainly has contact with the Mediterranean Chenopodiaceae flora. The contact of southeastern China with the Australia Chenopodiaceae flora, however, is very weak.     

广东南雄古新世一新的裂齿类

记述了广东南雄盆地早～中古新世上湖组上部发现的裂齿目一新属新种──杨氏华南兽（Ｈｕａｎａｎｉｕｓ ｙｏｕｎｇｉ ｇｅｎ． ｅｔ ｓｐ． ｎｏｖ．）。新属在上、下前日齿不臼齿化,上臼齿无次尖,下臼齿三角座和跟座均呈Ｖ形等方面显得原始。但在颊齿单面高冠,上臼齿原尖前、后脊分别与前、后附尖相连,小尖发育,具初始的次尖架,下臼齿略呈双曲拱柱状,具下后附尖等方面显示了向典型的裂齿类方向发展。     

Fossil Records in the Lythraceae

The Lythraceae (Myrtales) are a family of 28 genera and ca. 600 species constituting with the Combretaceae and sister family Onagraceae a major lineage of the Myrtales and including the former Sonneratiaceae, Duabangaceae, Punicaceae, and Trapaceae. The fossil record of the family is extensive and significant new discoveries have been added to the record in recent years. This review provides a vetted summary of fossils attributed to the Lythraceae, their geographic distributions, and their stratigraphic ranges. It anticipates the use of the information to generate robustly dated molecular phylogenies to accurately reconstruct the evolutionary and biogeographic history of the family. Fossils of 44 genera or form genera have been attributed to the Lythraceae; 24 are accepted here as lythracean. Fourteen of the 28 modern genera have fossil representatives: Adenaria, Crenea, Cuphea, Decodon, Duabanga, Lafoensia, Lagerstroemia, Lawsonia, Lythrum, Pemphis, Punica, Sonneratia, Trapa, and Woodfordia. Ten extinct genera are recognized. The most common kinds of fossil remains are seeds and pollen. The only fossil flower confidently accepted in the family is the extinct genus Sahnianthus from the Early Paleocene of India. The oldest confirmed evidence of the Lythraceae is pollen of Lythrum/Peplis from the Late Cretaceous (early Campanian, 82?81 Ma) of Wyoming. Seeds of Decodon from the late Campanian (73.5 Ma) of northern Mexico are next oldest. Sonneratia, Lagerstroemia, and extinct Sahnianthus first appear in the Paleocene of the Indian subcontinent; extinct Hemitrapa fruits first occur in the Paleocene of northwestern North America. Diversification of the Lythraceae occurred primarily during two major periods of global temperature change, during the Paleocene-Eocene Thermal Maximum and from the middle Miocene forward when temperatures decreased markedly and seasonality and dry-adapted vegetation types became more prominent. Fossils of the Lythraceae from South America and Africa are limited in number. The few dates available for South American genera are comparatively young and diversification of the largest genus, Cuphea (ca. 240 species), was mainly a Quaternary event. A phylogeny of the family is briefly explored and examples of specialized characters occurring in the oldest known genera are noted. The fossil record of the Lythraceae is presently too fragmentary to confidently reconstruct the early history of the family. The record indicates, however, that the family was well-diversified and widely dispersed globally over a wide latitudinal range by the end of the Paleocene.