Li-Bing Zhang

Phylogeny and quaternary history of the European montane/alpine endemic Soldanella (Primulaceae) based on ITS and AFLP variation.

Soldanella contains 16 species of herbaceous perennials that are endemic to the central and south European high mountains. The genus is ecogeographically subdivided into forest/montane and alpine species. Evolutionary relationships and large-scale biogeographic patterns were inferred from parsimony analyses of the internal transcribed spacer (ITS) regions of nuclear ribosomal DNA, and genetic distance analyses based on amplified fragment length polymorphism (AFLP) markers. The ITS region proved useful for examining subgeneric relationships and testing hypotheses on genus-wide divergence times, whereas the AFLP markers were suitable for studying relationships among closely related taxa and biogeographic patterns of divergence. Neither ITS nor AFLP data supported sectional delimitations, particularly those related to the grouping of S. alpina (sect. Soldanella) with S. pusilla (sect. Tubiflores), which may be the result of hybridization. Additional results and conclusions drawn are (1) Soldanella is derived from an ancestor of Asian origin with a montane ecology; (2) estimates of divergence times suggest a late Quaternary origin of the genus; (3) alpine species of sect. Tubiflores diverged from within a paraphyletic sect. Soldanella of mainly montane species; (4) alpine and montane species of Soldanella experienced different cycles of range expansion and contraction during late Quaternary climatic changes, resulting in differential patterns of geographic distribution; and (5) AFLP divergence among montane species from eastern Europe was lower than between alpine species; we hypothesize that the latter differentiated in allopatric regions of expansion during glacials, while the former experienced secondary contact at lower elevations in more southern refugia.

A community-derived classification for extant lycophytes and ferns

Phylogeny has long informed pteridophyte classification. As our ability to infer evolutionary trees has improved, classifications aimed at recognizing natural groups have become increasingly predictive and stable. Here, we provide a modern, comprehensive classification for lycophytes and ferns, down to the genus level, utilizing a community‐based approach. We use monophyly as the primary criterion for the recognition of taxa, but also aim to preserve existing taxa and circumscriptions that are both widely accepted and consistent with our understanding of pteridophyte phylogeny. In total, this classification treats an estimated 11 916 species in 337 genera, 51 families, 14 orders, and two classes. This classification is not intended as the final word on lycophyte and fern taxonomy, but rather a summary statement of current hypotheses, derived from the best available data and shaped by those most familiar with the plants in question. We hope that it will serve as a resource for those wanting references to the recent literature on pteridophyte phylogeny and classification, a framework for guiding future investigations, and a stimulus to further discourse.

Distribution of living Cupressaceae reflects the breakup of Pangea

Most extant genus-level radiations in gymnosperms are of Oligocene age or younger, reflecting widespread extinction during climate cooling at the Oligocene/Miocene boundary [∼23 million years ago (Ma)]. Recent biogeographic studies have revealed many instances of long-distance dispersal in gymnosperms as well as in angiosperms. Acting together, extinction and long-distance dispersal are likely to erase historical biogeographic signals. Notwithstanding this problem, we show that phylogenetic relationships in the gymnosperm family Cupressaceae (162 species, 32 genera) exhibit patterns expected from the Jurassic/Cretaceous breakup of Pangea. A phylogeny was generated for 122 representatives covering all genera, using up to 10,000 nucleotides of plastid, mitochondrial, and nuclear sequence per species. Relying on 16 fossil calibration points and three molecular dating methods, we show that Cupressaceae originated during the Triassic, when Pangea was intact. Vicariance between the two subfamilies, the Laurasian Cupressoideae and the Gondwanan Callitroideae, occurred around 153 Ma (124–183 Ma), when Gondwana and Laurasia were separating. Three further intercontinental disjunctions involving the Northern and Southern Hemisphere are coincidental with or immediately followed the breakup of Pangea.

The Deepest Splits in Chloranthaceae as Resolved by Chloroplast Sequences

Evidence from the fossil record, comparative morphology, and molecular phylogenetic analyses indicates that Chloranthaceae are among the oldest lineages of flowering plants alive today. Their four genera (ca. 65 species) today are disjunctly distributed in the Neotropics, China, tropical Asia, and Australasia, with a single species in Madagascar but none in mainland Africa. In the Cretaceous, Chloranthaceae occurred in much of Laurasia as well as Africa, Australia, and southern South America. We used DNA sequence data from the plastid rbcL gene, the rpl20‐rps12 spacer, the trnL intron, and the trnL‐F spacer to evaluate intra‐Chloranthaceae relationships and geographic disjunctions. In agreement with earlier analyses, Hedyosmum was found to be sister to the remaining genera, followed by Ascarina and \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

THE TEMPORAL COURSE OF QUATERNARY DIVERSIFICATION IN THE EUROPEAN HIGH MOUNTAIN ENDEMIC PRIMULA SECT. AURICULA (PRIMULACEAE)

Chloranthus+Sarcandra

Molecular circumscription and major evolutionary lineages of the fern genus Dryopteris (Dryopteridaceae)

\end{document} . Bayesian and parsimony analyses of the combined data yielded resolved and well‐supported trees except for polytomies among Andean Hedyosmum and Madagascan‐Australasian‐Polynesian Ascarina. The sole Asiatic species of Hedyosmum, Hedyosmum orientale from Hainan, China, was sister to Caribbean and Neotropical species. Likelihood ratio tests on the rbcL data set did not reject the assumption of a clock as long as the long‐branched outgroup Canella was excluded. Two alternative fossil calibrations were used to convert genetic distances into absolute ages. Calibrations with Hedyosmum‐like flowers from the Barremian‐Aptian or Chloranthus‐like androecia from the Turonian yielded substitution rates that differed by a factor of two, illustrating a perhaps unsolvable problem in molecular clock–based studies that use several calibration fossils. The alternative rates place the onset of divergence among crown group (extant) species of Hedyosmum at 60 or 29 Ma, between the Paleocene and the Oligocene; that among extant Chloranthus at 22 or 11 Ma; and that among extant Ascarina at 18 or 9 Ma, implying long‐distance dispersal between Madagascar and Australasia‐Polynesia.

A chloroplast phylogeny of Arisaema (Araceae) illustrates Tertiary floristic links between Asia, North America, and East Africa

Abstract A phylogenetic analysis of the Celastrales was performed using nuclear (18S, ITS 1, 26S rDNA) and plastid (atpB, matK, rbcL, trnL-F spacer) genes. In contrast to most previous studies, Celastrales and Malpighiales are resolved as being more closely related to one another than either are to Oxalidales. The Huaceae are well supported as the sister group to Oxalidales, not Celastrales, as had been previously proposed. The Lepidobotryaceae are unambiguously supported as sister to the clade consisting of Celastraceae and Parnassiaceae. The Parnassiaceae are well supported as members of an early branching lineage within Celastraceae, rather than as its sister group. Likewise, Pottingeria appears to be part of an early derived lineage of Celastraceae. Empleuridium is unambiguously supported as a derived member of Celastraceae, as are Brexia, Canotia, Siphonodon, Stackhousia, and Tripterococcus. Bhesa is unambiguously supported as a member of Malpighiales, though its relationships within the order remain unclear. Perrottetia should be transferred out of Celastraceae and into eurosids II, being closely related to Tapiscia and Dipentodon. These results help delimit the Celastrales and Celastraceae as morphologically more homogeneous taxa.

Mating system and stigmatic behaviour during flowering of Alpinia kwangsiensis (Zingiberaceae)

Primula sect. Auricula is one of only a few endemics of the European high mountains with a comparatively large number of species. We explored the section’s geographical origin, time of origin, and temporal course of diversification via parsimony, genetic distance, and lineages‐through‐time analyses based on the internal transcribed spacer (ITS) regions of nuclear ribosomal DNA. The taxa analyzed included 52 individuals representing all 25 species of the section, representatives of seven other European, Asian, and/or North American sections of the genus, and two species of Douglasia. We present evidence that sect. Auricula likely originated from an Asian ancestor at the end of the Late Tertiary, followed by its primary diversification into an “eastern” and “western” lineage at the Plio‐/Pleistocene boundary. Comparison with a constant rates null model of stochastic diversification‐extinction (birth‐death) demonstrates that diversification has proceeded nonrandomly through Quaternary times in both lineages. They display a pulse of speciation events occurring soon after their origin and relatively few such events occurring since. This pattern contrasts with the predictions of the Late Pleistocene origins hypothesis and implies unpredictability of the evolutionary response of sect. Auricula to the recurrent abiotic conditions of the Quaternary glacial‐interglacial cycles. We conclude that it is not necessary to invoke an increase in extinction rate. Rather, the observed slowdown of interspecific (and intraspecific) diversification in sect. Auricula toward the present likely results from a decrease in diversification rate due to ecological and/or geographical space‐filling processes.