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Phylogenetic interrelationships in the enlarged order Ericales were investigated by jackknife analysis of a combination of DNA sequences from the plastid genes rbcL, ndhF, atpB, and the mitochondrial genes atp1 and matR. Several well-supported groups were identified, but neither a combination of all gene sequences nor any one alone fully resolved the(More)
Gnetales comprise three unusual genera of seed plants, Ephedra, Gnetum, and Welwitschia. Their extraordinary morphological diversity suggests that they are survivors of an ancient, more diverse group. Gnetalean antiquity is also supported by fossil data. Dispersed "ephedroid" (polyplicate) pollen first appeared in the Permian >250 million years ago (Myr),(More)
BACKGROUND AND AIMS The extant species of the seed plant group Gnetales (Ephedra, Gnetum and Welwitschia) have been considered a remnant of a much greater, now extinct, diversity due to the pronounced differences in form and ecology among the genera. Until recently, this hypothesis has not been supported by evidence from the fossil record. This paper adds(More)
The fossil history of most extant seed plant groups is relatively well documented. Cycads, conifers and Ginkgo all have an extensive fossil record, and the understanding of early angiosperm diversity is increasing. The Gnetales are an exception. Few macrofossils have been described, and character evolution within the group is poorly known. Cratonia(More)
Morphological variation in Ephedra (Gnetales) is limited and confusing from an evolutionary perspective, with parallelisms and intraspecific variation. However, recent analyses of molecular data provide a phylogenetic framework for investigations of morphological traits, albeit with few informative characters in the investigated gene regions. We document(More)
Despite extensive efforts, parts of the phylogeny of the angiosperm family Rubiaceae has not been resolved and consequently, character evolution, ancestral areas and divergence times of major radiations are difficult to estimate. Here, phylogenetic analyses of 149 taxa and five plastid gene regions show that three enigmatic genera are sisters to(More)
Knowledge on fossil and evolutionary history of the Gnetales has expanded rapidly; Ephedra and ephedroids as well as the Gnetum-Welwitschia clade are now well documented in the Early Cretaceous. However, hypotheses on evolutionary relationships among living and fossil species are hampered by restricted knowledge of morphological variation in living groups(More)
Gnetalean compression-impression fossils are described from the Early Cretaceous Yixian Formation, Liaoning Province, north-eastern China, and assigned to six species of Liaoxia Cao et S.Q. Wu. The fossils have opposite-decussate phyllotaxis and cones comprising 2–12 pairs of bracts. Ovulate cones have seeds typically in a distal position. The species(More)
Despite extensive efforts, there are unresolved questions on evolutionary relationships in the angiosperm family Rubiaceae. Here, information from six loci and 149 Rubiaceae taxa provide new insights. Acranthera and Coptosapelta are strongly supported as sisters. Pollen grains of Acranthera possess several features common in Rubiaceae, but amongst potential(More)