Systematic implications of seed coat diversity in Gaultherieae (Ericaceae)

The seed morphology of 90 samples from 83 species of tribe Gaultherieae (Chamaedaphne, Diplycosia, Eubotryoides, Eubotrys, Gaultheria and Leucothoe) and relatives in tribes Andromedeae (Andromeda and Zenobia) and Vaccinieae (Satyria) was investigated with stereoscopic and scanning electron microscopy. Seeds exhibit variation in shape, colour, size, wing, hilum region, primary ornamentation and epidermal cells. Non‐metric multidimensional scaling (NMDS) analysis based on selected seed characters supports the affinities of some groups within Gaultherieae at various taxonomic levels. Seed characters corroborate the delimitation of Andromeda, Chamaedaphne, Leucothoe, Satyria and Zenobia and Gaultheria series Trichophyllae, series Hispidulae, section Amblyandra and section Brossaeopsis. Parsimony optimization of seed characters onto a previously published phylogenetic estimate of Gaultherieae reveals that small seeds have evolved from larger seeds and an areolate seed coat has evolved from a reticulate seed coat. Optimization also suggests that several seed character states are synapomorphies or potential synapomorphies for some major clades of Gaultherieae. Seeds of Gaultherieae from East Asia, temperate North America and the Pacific are more diverse than those from tropical America. Samples from the eastern Himalaya possess the highest variation in seed morphology. The wing and bulging edge cells observed in seeds of Leucothoe suggest dispersal by wind. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162 , 477–495.     

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.     

Epidermal micromorphology in Dioon: did volcanism constrain Dioon evolution?

The genus Dioon occupies an important phylogenetic position as sister to the other Zamiaceae. However, its epidermal morphology is still poorly known. We employed scanning and transmission electron microscopy, confocal microscopy and light microscopy to examine the epidermal and cuticular morphology of 12 of the 14 currently recognized species of Dioon, examining cultivated plants and herbarium specimens. Epidermal characters separate Dioon quite clearly from the other genera of the cycads. Within the genus, the major subgroups can be distinguished by their epidermal morphology. Some characters, such as the degree of stomatal protection, reflect ecological specializations in species within the subgroups. Several epidermal characters of the crown group Dioon seem to be absent in the Cenozoic fossils usually associated with the genus, which have been used as calibrations in many recent molecular dating analyses. The presence of similar characters in a Mesozoic fossil adapted to volcanic stress offers a new key in the interpretation of Dioon evolution. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 236–254.     

An assessment of the status of Polycirridae genera (Annelida: Terebelliformia) and evolutionary transformation series of characters within the family

A phylogenetic analysis was performed to determine the monophyly of non‐monotypic genera of the terebelliform family Polycirridae, i.e. Polycirrus, Amaeana, Lysilla, and Hauchiella, and the evolution of characters among members of this clade. The monotypic genera, Enoplobranchus and Biremis, were also included, together with members of both known species in Hauchiella. Representative species were included for remaining genera: 14 species of Polycirrus, six species of Amaeana, and six species of Lysilla. Out‐groups consisted of representatives of Spionidae, Cirratulidae, and Sabellariidae, as well as several species of Telothelepodidae. A total of 40 in‐ and out‐group species were coded for 50 subjects (‘characters’) and 117 subject–predicate relationships (‘states’). Although results are consistent with recent phylogenetic studies within Terebelliformia that suggest Polycirridae monophyly, only Hauchiella was found to be monophyletic, albeit part of the more inclusive clade comprising remaining polycirrid genera. Evolutionary transformation series are discussed for selected characters in relation to the non‐monophyly of Polycirrus, Lysilla, and Amaeana. Implications for the use of supraspecific taxa as ‘taxonomic surrogates’ are highlighted. The definition of Polycirridae is emended. © 2015 The Linnean Society of London     

The effect of shade on leaf structure and physiology of tree seedlings from a mixed dipterocarp forest

This study builds upon past work investigating seedling leaf physiology and structure among tropical trees. We seek to explain how related and unrelated species and genera co‐occur in relation to varying amounts of shade. Seedlings of eight Sri Lankan rain forest tree species in three genera (Dipterocarpus, Mesua, Shorea section Doona) were grown for 2 years in four treatments that simulated a variety of shade environments across the understorey of a rain forest. All three genera comprise major canopy tree species of mixed dipterocarp forest, a widespread and important Asian tropical forest type. Compared with the other genera, Dipterocarpus spp. had the largest leaves, the thinnest leaf blades and relatively high rates of stomatal conductivity across all shade treatments, making them water‐loving species sensitive to droughty soils. Mesua spp. had intermediate sized leaves, with the thickest leaf blades and palisade mesophyll layers, the highest stomatal densities, the smallest aperture sizes and the lowest rates of stomatal conductance, making them the most water conservative. Shorea spp. were generally intermediate in blade and palisade mesophyll dimensions between Dipterocarpus spp. and Mesua spp., but they had the smallest leaves. Greater differences among genera than among species within genera were apparent, but species differences within genera were also apparent. Differences among genera and species conform to their known successional status and topographical affinities and provide a more comprehensive understanding of species site adaptation. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167 , 332–343.     

Root causes of phylogenetic incongruence observed within basal sauropodomorph interrelationships

The relationships among basal sauropodomorphs are controversial. Results of cladistic analyses vary from a fully paraphyletic assemblage to a monophyletic core‐prosauropod. We apply the comparative cladistics method to three published cladistic analyses of sauropodomorph dinosaurs, in order to identify root causes for differences between phylogenetic results. Except for three taxa (Saturnalia, Thecodontosaurus, and Efraasia) and one clade (Gravisauria), the remaining genera are recovered with conflicting positions. The comparative method is based on indices that allow for the quantification of the degree of similarity in characters and character states among analyses. A comparison of primary data, character selection, and scoring highlights significant discrepancies in data sets. Our results suggest that one character out of two varies from one analysis to the other. These are the root causes for the phylogenetic incongruence observed. The hurdle of the phylogenetic definition of the clade Sauropoda, which has been defined in four different ways, is also treated. We concur with several recent papers following the first node‐based definition of Sauropoda. © 2015 The Linnean Society of London     

Leaf epidermal micromorphology of Cercis (Fabaceae: Caesalpinioideae)

The micromorphology of leaf epidermal cells and stomata of all eight species and one form (11 samples) of Cercis were observed by scanning electron microscopy and light microscopy. Both the adaxial and abaxial epidermal cells are polygonal or irregular in shape; the anticlinal walls are straight and arched or undulate. Two types of stomata, which occur only on the abaxial surface of the leaves, are found in the genus. The atypical paracytic type is present in only one species, Cercis chingii, and the anomocytic type is present in all other species. Interspecific differences are minor in the genus with regard to leaf epidermal characters, except for C. chingii, which is characterized by atypical paracytic‐type stomata, a two‐lipped outer stomatal rim, the highest stomatal density and undulate and densely pitted anticlinal walls in the adaxial epidermis. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 539–547.     

Phylogenetic inference using discrete characters: performance of ordered and unordered parsimony and of three‐item statements

The cladistic literature does not always specify the kind of multistate character treatment that is applied for an analysis. Characters can be treated either as unordered transformation series or as rooted [three‐item analysis (3ia)] or unrooted state trees (ordered characters). We aimed to measure the impact of these character treatments on phylogenetic inference. Discrete characters can be represented either as rows or columns in matrices (e.g. for parsimony) or as hierarchies for 3ia. In the present study, we use simulated and empirical examples to assess the relative merits of each method considering both the character treatment and representation. We measure two parameters (resolving power and artefactual resolution) using a new tree comparison metric, ITRI (inter‐tree retention index). Our results suggest that the hierarchical character representation not only results (with our simulation settings) in the greatest resolving power, but also in the highest artefactual resolution. Our empirical examples provide equivocal results. Parsimony unordered states yield less resolving power and more artefactual resolutions than parsimony ordered states, both with our simulated and empirical data. Relationships between three operational taxonomic units (OTUs), irrespective of their relationships with other OTUs, are called three‐item statements (3is). We compare the intersection tree (which reconstructs a single tree from all of the common 3is of source trees) with the traditional strict consensus and show that the intersection tree retains more of the information contained in the source trees. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 914–930.     

Character divergences and convergences in canopy-dwelling Loranthaceae

The Loranthaceae is the largest plant family with aerial branch parasites termed mistletoes. Three genera of Loranthaceae are terrestrial root parasites and the remaining 72 genera are aerial parasites. Several characters, including habit, haustorial type, germination pattern, pollen morphology, chromosome number, inflorescence morphology and flower merosity, fusion, symmetry and size, are considered to reflect evolutionary relationships within the family. Convergence is a common evolutionary pattern and can confound interpretations of evolution. We investigated character evolution by mapping character states onto a phylogenetic tree based on the nuclear ITS and chloroplast trnL–trnF regions. Convergences in form were found in several characters, including habit, haustorial type, flower symmetry and merosity. These convergences typically correspond to ecological parameters such as pollination syndrome or stresses associated with the canopy habit. Other characters such as chromosome number and germination pattern illustrate divergent evolution among clades.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 101–113.     

Scale Biogenesis in Synurophycean Protists: Phylogenetic Implications

The Synurophyceae is a class of golden-brown, freshwater, photosynthetic flagellates with a world-wide distribution. A well-developed taxonomy exists where genera and species are distinguished by colony or cell morphology or by the siliceous scales that cover the cells. However, phylogenetic relationships within the class are poorly understood, and incongruous taxonomic concepts occur. This study reviews scale morphology from field-collected samples and controlled culturing experiments as well as from studies of scale biogenesis. The information is used to identify homologous silicification surfaces among taxa and to document the diversity of the resulting scale structures. Thirty-two character states are coded into 11 characters in a cladistic analysis of 13 pivotal taxa. Colonial species are emphasized. One most-parsimonious phylogenetic tree is found (HI = 0, CI = 1). Synura lapponica is shown to be most closely related to Tessellaria volvocina. S. sphagnicola emerges at the base of the tree. Mallomonas caudata and the S. petersenii clade emerge from within Sectio Synura. Chrysodidymus synuroideus appears as an ancestral taxon in the Synura spinosa-like clade (i.e., Series Spinosae). The poorly understood developmental bases for some characters, especially secondary scale structures, are identified and may help focus future research.     

Comparative morphology of the leaf epidermis in Schisandra (Schisandraceae)

The leaf epidermis of 127 samples representing ten species within Schisandra Michaux. and one species of the related genus, Kadsura Kaempf. ex Juss., was investigated using light and scanning electron microscopy. Many characters of the leaf epidermis in Schisandra , such as pattern of epidermal cells, type of stomata, shape of guard cell pairs and cuticular ornamentation, are usually constant within species and thus make good characters for studying the relationship between and within genera. A new character, rim number, of the outer stomatal rim in the genus is introduced. It is shown that double outer stomatal rims occur only in evergreen Schisandra species, whereas a single rim occurs in deciduous species. This character supports the classification of Schisandra into two subgenera based on habit and androecial organs. This classification is also supported by additional morphological and molecular taxonomic characters. Kadsura coccinea (Lem.) Smith A. C. is the most primitive taxon in the related genus Kadsura . The outer stomatal rim of this species also has double rims. Combined with morphological and molecular evidence, this suggests that Schisandra and Kadsura are closely related and may share a recent common ancestor.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 39–56.     

Molecular phylogeny of sea snakes reveals a rapidly diverged adaptive radiation

Evolutionary relationships within and between the marine hydrophiine sea snake groups have been inferred primarily using morphological characters, and two major groups traditionally are recognized. The Aipysurus group comprises nine species in two genera, and the taxonomically chaotic Hydrophis group comprises as many as 40 species, of which 27 are generally allocated to the genus Hydrophis and 13 to ten additional genera. In addition to these two major groups are three putatively ‘primitive’ monotypic genera, Hydrelaps darwiniensis, Ephalophis greyi and Parahydrophis mertoni. The present study investigated the evolutionary relationships of 23 representative species of marine hydrophiines, comprising 15 species from the Hydrophis group, six species from the Aipysurus group, and H. darwiniensis and P. mertoni, to address two broad aims. First, the aim was to provide a robust phylogeny for sea snakes to test previous phylogenetic hypotheses based on morphology, and thus provide some taxonomic stability to the group. Second, there was interest in evaluating the hypothesis that the Hydrophis group might represent a rapidly diverged adaptive radiation. A large mitochondrial DNA data set based on the cytochrome b gene (1080 bp, 401 parsimony informative) and the 16S rRNA gene (510 bp, 57 parsimony informative) was assembled and these data were analysed using parsimony, maximum‐likelihood and Bayesian approaches. All analyses yielded virtually the same optimal tree, confirming that hydrophiine sea snakes comprise at least three lineages. The Aipysurus group formed a strongly supported and well‐resolved monophyletic clade. The Hydrophis group also formed a strongly supported clade; however, resolution among the genera and species was very poor. Hydrelaps darwiniensis and P. mertoni formed a sister clade to the Hydrophis lineage. Our phylogeny was used to test the validity of previous taxonomic and phylogenetic hypotheses, and to demonstrate that the genus Hydrophis is not monophyletic. Genetic diversity relative to phenotypic diversity is four to seven times greater in the Hydrophis lineage compared with the Aipysurus lineage. The topology of our phylogenetic hypothesis, combined with the levels of genetic divergence relative to morphological diversity, demonstrate that the Hydrophis lineage represents a rapidly diverged adaptive radiation. The data are consistent with the hypothesis that this adaptive radiation may be due to historical sea level fluctuations that have isolated populations and promoted speciation. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89 , 523–539.     

NUCLEAR RIBOSOMAL DNA PHYLOGENY OF HALIMEDALES REVEALS SEVERAL POLYPHYLETIC GENERA

Halimedales (Chlorophyta) are widely distributed in reefs and lagoons throughout the tropics and subtropics. One genus, Chlorodesmis, consists of simple, branching siphons that persist into the mature sexual phase. In most other genera, only the juvenile stages exhibit such simple anatomy. Their mature, often‐calcified thalli possess complex siphonal anatomy and differentiation depending on the location in the thallus. We obtained a nuclear ribosomal DNA phylogeny encompassing many genera in order to unravel the evolution of this complexity. Results pinpoint Caulerpa as outgroup to a clade with all other genera included in this study. The first dichotomy separates Halimeda from the remaining genera. Distinct gametangial anatomy defines these two principal clades. Within the remainder, Tydemania and its sister Flabellia are nearest neighbors to a clade containing Rhipocephalus, Udotea, Penicillus and Chlorodesmis. The latter three genera are polyphyletic. Therefore, character states of thallus superstructure defining these genera appear to be homoplasies. Chlorodesmis represents a case of neoteny where the juvenile stage persists into reproductive maturity. We will evaluate which morphological characters do change state in agreement with the molecular phylogeny and can, therefore, serve as diagnostic characters for a more natural classification.     

An investigation of the cranial evolution of Asian pitvipers (Serpentes: Crotalinae), with comments on the phylogenetic position of Peltopelor macrolepis

Guo, P., Jadin, R.C., Malhotra, A. and Li, C. 2009. An investigation of the cranial evolution of Asian pitvipers (Serpentes: Crotalinae), with comments on the phylogenetic position of Peltopelor macrolepis—Acta Zoologica (Stockholm) 91 : 402–407. We investigated the evolution of 12 cranial characters of 31 species of Asian pitvipers by examining the character state changes on a consensus tree modified from broadly consistent molecular results. We found that these characters appear stable with only one intraspecific polymorphism. Nine of the 12 characters form useful synapomorphies, whereas three are ambiguous and evolutionarily plastic. Clades that are supported with numerous apomorphies are the Trimeresurus group [consisting of the recently defined genera Trimeresurus sensu Malhotra and Thorpe (2004) , Parias, Popeia, Viridovipera, Himalayophis, and Cryptelytrops] and the genera Protobothrops, Parias, and Viridovipera. Two species previously considered as congeners but now known to be distantly related, Ovophis monticola and ‘Ovophis’okinavensis, have nearly identical character states, demonstrating substantial convergence in cranial characters. Finally, we attempt to infer the phylogenetic position of Peltopelor macrolepis by comparing its cranial features with that of other pitvipers.     

根据叶表皮微形态特征试论新麦草属、芒麦草属和三柄麦属间的系统关系

观察了禾本科新麦草属、芒麦草属和三柄麦属主要代表种的叶片表皮形态学特征,总结了三属植物叶表皮结构的异同,探讨了叶表皮特征的分类学意义。同时,根据三属植物叶表皮性状的演化趋势,分析了各属的演化关系和系统位置。结果表明,新麦草属最原始,芒麦草属较进化,三柄麦属最高级;新麦草属可能直接派生了较进化的芒麦草属,并在芒麦草属的基础上进而产生了最高级的三柄麦属。三柄麦属、芒麦草属和新麦草属的这一系统关系同它们外部形态上三联小穗的演化趋势是相互印证的。     

Evolution of trichomes and its systematic significance in Salvia (Mentheae; Nepetoideae; Lamiaceae)

We have investigated the trichome characteristics in representative species of Salvia and Pleudia in order to evaluate this source of morphological evidence for addressing problems regarding generic delimitation and subgeneric classification. Trichomes of 46 Salvia spp., representing three subgenera in Iran, were investigated using light microscopy and scanning electron microscopy. General trichome characteristics were constant among different populations of a certain species, but showed a degree of variability useful in the delimitation of taxa, specifically at lower taxonomic levels. Trichome characters of taxonomic interest are as follows: types of glandular hair; number of composing cells (uni‐, bi‐ or multicellular); size and thickness; branching pattern; and presence of papillae on the surface. Non‐glandular trichomes can be simple and branched. Glandular trichomes can be stalked, subsessile or sessile. Our investigation reveals the usefulness of such characters in providing fundamental taxonomic criteria for taxon delimitation in these genera at various levels, especially at the specific rank. Furthermore, the data presented here indicate the potential applicability of such characters in the determination of evolutionary trends in Salvia and allies. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2016, 180 , 241–257.     

中国凤仙花科植物叶表皮特征及其分类学意义

利用光学显微镜观察凤仙花科106份样本材料、36种代表植物的叶表皮微形态特征。结果表明:该科植物叶表皮微形态特征种内稳定,对于种间及属间关系的界定具有重要的分类学价值。上表皮细胞的形状及垂周壁的式样种间差异明显,各分类群间有明显的界限,是种间界定的重要依据,因此上表皮微形态特征具有重要的的分类学价值,基于上表皮的微形态特征将研究的36种代表植物划分为5个类型。下表皮的微形态特征虽更为多样,种间差异显著,可用于种间界定,但对于属下划分难以提供有价值的性状。该科植物叶表皮微形态特征与宏观形态特征的相关性较弱,与地理分布格局的相关性较强,关系更为密切。同一地理分布区域内的种类宏观形态特征虽然差别明显,但叶表皮微形态特征却表现出较强的一致性,这似乎也反映了叶表皮微形态这一性状受环境饰变的影响比较明显。综上所述,叶表皮微形态特征可为凤仙花科的系统发育,尤其是凤仙花属种间界定提供有价值的分类学佐证