A New Molecular Phylogeny and a New Genus,Pendulorchis, of the Aerides–Vanda Alliance (Orchidaceae: Epidendroideae)

Background

The Aerides–Vanda alliance is a complex group in the subtribe Aeridinae (subfamily Epidendroideae, Orchidaceae). Some phylogenetic systems of this alliance have been previously proposed based on molecular and morphological analyses. However, several taxonomic problems within this alliance as well as between it and its allies remain unsolved.

Methodology/Principal Findings

We utilized ITS and five plastid DNA regions in this phylogenetic analysis. Consensus trees strongly indicate that the Aerides–Vanda alliance is monophyletic, and the 14 genera of this alliance can be grouped into the following clades with 14 subclades: 1. Aerides, comprising two subclades: Rhynchostylis and Aerides; 2. Ascocentropsis; 3. Papilionanthe; 4. Vanda, comprising five subclades: Neofinetia, Christensonia, Seidenfadenia, Ascocentrum, and Vanda–Trudelia, in which Vanda and Trudelia form a subclade; 5. Tsiorchis, comprising three subclades: Chenorchis, Tsiorchis, and two species of Ascocentrum; 6. Paraholcoglossum; and 7. Holcoglossum. Among the 14 genera, only Ascocentrum is triphyletic: two species of the Ascocentrum subclade, an independent subclade Ascocentrum subclade in the Tsiorchis clade; the Ascocentrum subclade in the Vanda clade; and one species in the Holcoglossum clade. The Vanda and Trudelia species belong to the same subclade. The molecular conclusion is consistent with their morphological characteristics.

Conclusions

We elucidate the relationship among the 14 genera of the Aerides–Vanda alliance. Our phylogenetic results reveal that the Aerides–Vanda alliance is monophyletic, but it can be divided into 14 genera. The data prove that Ascocentrum is triphyletic. Plants with elongate-terete leaves and small flowers should be treated as a new genus, Pendulorchis. Saccolabium himalaicum (Ascocentrum himalaicum) should be transferred to Pendulorchis. Ascocentrum pumilum, endemic to Taiwan, should be transferred to Holcoglossum. A new combination, Holcoglossum pumilum, was also established. Trudelia should not be recognized as an independent genus. Two new species, Pendulorchis gaoligongensis and Holcoglossum singchianum, were described as well.     

Paraholcoglossum and Tsiorchis, two new orchid genera established by molecular and morphological analyses of the Holcoglossum alliance

Background

Holcoglossum is a small orchid genus of 12 species ranging from SW China to Thailand and NE India. Although molecular and morphological analyses have been performed to establish the phylogenetic relationships within this genus, the interspecific relations and its relations with allied genera, such as Rhynchostylis, Aerides and Vanda, remain unclear.

Methodology/Principal Findings

In addition to morphological analysis, maximum parsimony, maximum likelihood, and Bayesian inference analyses were performed based on fragments of the nuclear ITS and chloroplast trnL-F and matK genes of 31 taxa (15 Holcoglossum, 14 Aeridinae, 2 outgroups) representing all major clades of the Holcoglossum alliance. The results suggest that Holcoglossum is triphyletic, comprising three clades: the Holcoglossum clade, its sister clade, and a distant clade more closely related to Rhynchostylis, Aerides, and Vanda than to the Holcoglossum clade. The Holcoglossum clade is further divided into three subclades; the genetic distances between these three subclades also support this delimitation. The molecular conclusion is consistent with their distinct morphological characters.

Conclusions

We propose that the latter two clades comprise two new genera, Paraholcoglossum and Tsiorchis, and Holcoglossum clade divides into three sections. In addition, a new section, Holcoglossum sect. Nujiangensia, and a new species, Holcoglossum linearifolium, are proposed. Some new combinations are made, and a new scheme is provided for the classification of all species of Holcoglossum, Paraholcoglossum, and Tsiorchis.     

八角目(Illiciales)植物花被片表皮比较形态

在光学显微镜和扫描电镜下,观察了八角科(Illiciaceae)八角属(Illicium Linn.)2组11种20个材料、五味子科(Schisandraceae)南五味子属(Kadsura Ksempf. ex Juss.)2亚属2组8种15个材料和五味子属(Schisandra Michx.)2亚属4组6种17个材料的花被片表皮形态特征。首次报道了八角目2个科（八角科和五味子科）3个属（八角属、南五味子属和五味子属）植物花被片表皮细胞的形状、分泌细胞的形状及分布、气孔器的形状及分布、花被片表面的纹饰。通过与八角目2个科3个属植物的叶表皮形态比较,发现花被片表皮气孔器外拱盖均为单层,与叶表皮气孔器外拱盖层数（常绿种类为双层和落叶种类为单层）之间没有相关性,还在五味子科中发现2个新的性状（气孔对和环列型气孔）。通过对两性花、雌花和雄花花被片表皮观察,发现花被片表皮形态与花的性别之间没有相关性。通过对八角属、南五味子属和五味子属花被片表皮比较,发现五味子属与南五味子属相比,其花被片表皮表现出更多的衍生性状;南五味子属与八角属相比,前者花被片表皮具有更多的衍生性状;而南五味子属花被片表皮形态与五味子属的相似性程度较大,支持五味子科包含南五味子属和五味子属、八角科包含八角属的观点。     

Diversity and phylogeny of percolomonads based on newly discovered species from hypersaline and marine waters

Percolomonads are common freshwater, marine and hypersaline tetraflagellated organisms. Current phylogenetic analyses of eukaryotes comprise only two species of this underinvestigated family. Here, we studied the morphology, salinity tolerance and 18S rDNA gene-based phylogeny of seven percolomonad cultures. We describe three new genera and five novel species of Percolomonadida based on phylogenetic distances and morphological characteristics: Barbelia atlantica, B. abyssalis, Lula jakobsenorum, Nakurumonas serrata and Percolomonas doradorae.The new species show features typical for percolomonads, one long flagellum for skidding, three shorter flagella of equal length and a ventral feeding groove. The new species comprise organisms living in marine and athalassic hypersaline waters with salinity ranging from 10 to 150 PSU. Based on these novel taxa, the taxonomy and phylogeny of Percolatea was extended and further resolved.     

Taxonomic and ecological implications of leaf cuticular morphology in Castanopsis, Castanea, and Chrysolepis

Leaves of 41 species of Castanopsis, six species of Castanea, and Chrysolepis chrysophyllum Hjelmq. were examined. In Castanopsis, all species possessed cyclocytic stomata with thickened subsidiary cells; thin-walled peltate trichomes are the most frequent type on the abaxial surface of the leaves of this genus. In Castanea, stomata are transitional between cyclocytic and anomocytic; thin-walled peltate trichomes were recorded for the first time on the abaxial surface of Castanea leaves. In Chrysolepis, cyclocytic stomata with non-thickened subsidiary cells and thick-walled peltate trichomes were observed. The thickened subsidiary cells support the placement of the “fissa-group” in Castanopsis. The results of this study support the idea that Castanopsis and Castanea are sister groups. Thick-walled peltate trichomes were only recorded in Chrysolepis, thus supporting its taxonomic separation from Castanopsis. The phylogenetic distribution of trichome types among genera of Fagaceae is summarized. The evolutionary trends of trichome types in Castanopsis are discussed, as are the implications of stomatal and trichome features on fossil identification and ecology.     

华北地区繁缕属（Stellaria L.）植物叶表皮微形态特征研究

采用光学显微镜,对华北地区分布的繁缕属植物16种2变种,其它4属4种植物的叶表皮微形态进行了观察。结果表明：繁缕属植物叶片的下表皮均存在气孔器,而上表皮仅少数种类缺乏气孔器。气孔器类型比较多样,有不等细胞型、无规则型、无规则四细胞型;表皮细胞主要为不规则型,垂周壁从平直、弓形、浅波状、波状、到深波状;上表皮气孔指数在5.23~31.65之间;下表皮气孔指数在10.02~29.44。叶表皮被毛或无,毛被分为星状毛、腺柔毛、柔毛、绢毛。该研究说明叶表皮的微形态特征在种间差异明显,可以为分种及属间亲缘关系的探讨提供依据,但是对组的划分存在一定的局限性。     

Comparative leaf anatomy and morphology of some neotropical Rutaceae: Pilocarpus Vahl and related genera

Previous anatomical studies have been restricted to the foliar aspects of Pilocarpus. However, no anatomical studies analyzing the foliar aspects of Pilocarpus in relation to related genera have been carried out. Therefore, the aim of this study was to identify characters for future taxonomic and phylogenetic studies in Rutaceae, particularly in Pilocarpus, and to discuss the characteristics associated with the simple or compound leaf condition for the group. The petiole and the leaf blade of 14 neotropical Rutaceae species were analyzed, and the following characteristics were observed in all leaves studied: stomata on both surfaces; secretory cavities, including mesophyll type; camptodromous?Cbrochidodromous venation pattern; and free vascular cylinder in the basal region of the petiole. Additional promising characters were identified for future taxonomic and phylogenetic studies in the Rutaceae family, especially for the Pilocarpus genera.     

Phylogenetics of Stelis and closely related genera (Orchidaceae: Pleurothallidinae)

Stelis, one of the largest genera within Pleurothallidinae, was recently recircumscribed to include a few hundred more species, most of which had previously been assigned to Pleurothallis. Here, a new phylogenetic analysis of Stelis and closely related genera based on DNA sequences from nuclear ITS and chloroplast matK, based on a much larger sample, is presented; it includes more than 100 species assigned to Stelis and covers all proposed groupings within the genus, many of which have not previously been represented. Clades are proposed to enable easier discussion of groups of closely related species; each clade is characterized morphologically, ecologically, and geographically to explain the evidence found in the molecular analysis. Discussion of the evolutionary trends of character states found in the genus in its broad sense is given. The current taxonomy of the group is given and the possible taxonomical implications of the findings presented here are discussed.     

中国五种仙茅科植物叶形态及其分类学意义

为澄清仙茅科属间界限不清的分类学问题,该文以中国仙茅科3属5种植物为研究对象,利用显微镜、扫描电镜和石蜡切片技术,观察了其叶形态、叶表皮显微特征和叶解剖特征。结果表明:(1)叶形态有小型平整叶、中型波状叶、大型折扇状叶三种。(2)叶表皮毛状体结构为单细胞单列,可分为长柔毛、糙伏毛和星状柔毛三类。(3)叶表皮细胞有六边形和五边形,气孔为平列型和椭圆形,气孔大小和气扎密度呈反比。(4)叶表皮蜡质纹饰有光滑、颗粒、屑状和壳状四类。(5)叶中脉横切面分为平整型和龙骨型,维管束有圆形和椭圆形,叶表皮厚度与表皮细胞具有正相关性。对5种植物的叶形态和叶解剖特征比较分析认为,一些特征组合有助于理解仙茅科属间的亲缘关系和物种鉴定,支持大叶仙茅属独立于仙茅属。     

Comparative anatomy and morphology of nectar-producing Melastomataceae

Background and Aims

Most neotropical Melastomataceae have bee-pollinated flowers with poricidal anthers. However, nectar rewards are known to be produced in about 80 species in eight genera from four different tribes. These nectar-producing species are pollinated by both vertebrates and invertebrates.

Methods

The floral morphology and anatomy of 14 species was studied in six genera of nectar-producing Melastomataceae (Blakea, Brachyotum, Charianthus, Huilaea, Meriania and Miconia). Anatomical methods included scanning electron microscopy, and serial sections of paraffin-embedded flowers.

Key Results

All vertebrate-pollinated melastome flowers have petals that do not open completely at anthesis, thus forming a pseudo-tubular corolla, while closely related species that are bee pollinated have rotate or reflexed corollas. In most species, nectar secretion is related to stomatal or epidermal nectaries and not filament slits as previously reported. Moreover, the nectar is probably supplied by large vascular bundles near the release area. Blakea and Huilaea have nectary stomata located upon the dorsal anther connective appendages. Brachyotum also has nectary stomata on the anther connectives, but these are distributed lengthwise along most of the connective. Meriania may release nectar through the anther connective, but has additional nectary stomata on the inner walls of the hypanthium. Miconia has nectary stomata on the ovary apex. Charianthus nectaries were not found, but there is circumstantial evidence that nectar release occurs through the epidermis at the apex of the ovary and the lower portions of the inner wall of the hypanthium.

Conclusions

Nectar release in Melastomataceae is apparently related to nectary stomata and not filament slits. The presence of nectary stomata on stamens and on ovary apices in different lineages suggests that the acquisition of nectaries is a derived condition. Nectary location also supports a derived condition, because location is strongly consistent within each genus, but differs between genera.Key words: Blakea, Brachyotum, Charianthus, Huilaea, Meriania, Melastomataceae, Miconia, nectaries, nectary stomata, pollination     

南五味子属（五味子科）植物叶表皮形态特征

在光学显微镜和扫描电镜下,观察了南五味子属（Kadsura Kaempf. ex. Juss.）全属11种,八角属（Illicium Linn.）2种,共108个样品的叶表皮特征。在南五味子属中,叶表皮细胞的形状、叶表皮表面的纹饰、气孔器的形状、气孔极区的形状、表皮毛的有无等性状能用于研究南五味子属种间关系,以及与五味子属（Schisandra Michaux）和八角属之间的关系。在八角目（Illiciales）中发现的一个新分类学性状（叶表皮表面具角质网纹）,支持将南五味子属分为离蕊南五味子亚属（Subg. Cosbaea）和南五味子亚属（Subg. Kadsura）。根据叶表皮形态特征,支持将南五味子亚属分为南五味子组（Sect. Kadsura）和肉蕊组（Sect. Sarcocarpon）,支持R. M. K. Saunders和林祁对某些种的归并处理。根据与五味子属和八角属叶表皮形态特征的比较,认为这3个属的叶表皮形态特征相似,但南五味子属叶表皮形态比五味子属和八角属的叶表皮形态复杂,不支持将五味子科（Schisandraceae）从八角目（Illiciales）中分出而成立五味子目（Schisandrales）的观点。     

A single-cell sequencing approach to the classification of large, vacuolated sulfur bacteria

The colorless, large sulfur bacteria are well known because of their intriguing appearance, size and abundance in sulfidic settings. Since their discovery in 1803 these bacteria have been classified according to their conspicuous morphology. However, in microbiology the use of morphological criteria alone to predict phylogenetic relatedness has frequently proven to be misleading. Recent sequencing of a number of 16S rRNA genes of large sulfur bacteria revealed frequent inconsistencies between the morphologically determined taxonomy of genera and the genetically derived classification. Nevertheless, newly described bacteria were classified based on their morphological properties, leading to polyphyletic taxa. We performed sequencing of 16S rRNA genes and internal transcribed spacer (ITS) regions, together with detailed morphological analysis of hand-picked individuals of novel non-filamentous as well as known filamentous large sulfur bacteria, including the hitherto only partially sequenced species Thiomargarita namibiensis, Thioploca araucae and Thioploca chileae. Based on 128 nearly full-length 16S rRNA-ITS sequences, we propose the retention of the family Beggiatoaceae for the genera closely related to Beggiatoa, as opposed to the recently suggested fusion of all colorless sulfur bacteria into one family, the Thiotrichaceae. Furthermore, we propose the addition of nine Candidatus species along with seven new Candidatus genera to the family Beggiatoaceae. The extended family Beggiatoaceae thus remains monophyletic and is phylogenetically clearly separated from other related families.     

A Phylogeny of the Family Poritidae (Cnidaria,Scleractinia) Based on Molecular and Morphological Analyses

The family Poritidae formerly included 6 genera: Alveopora, Goniopora, Machadoporites, Porites, Poritipora, and Stylaraea. Morphologically, the genera can be differentiated based on the number of tentacles, the number of septa and their arrangement, the length of the polyp column, and the diameter of the corallites. However, the phylogenetic relationships within and between the genera are unknown or contentious. On the one hand, Alveopora has been transferred to the Acroporidae recently because it was shown to be more closely related to this family than to the Poritidae by previous molecular studies. On the other hand, Goniopora is morphologically similar to 2 recently described genera, Machadoporites and Poritipora, particularly with regard to the number of septa (approximately 24), but they have not yet been investigated at the molecular level. In this study, we analyzed 93 samples from all 5 poritid genera and Alveopora using 2 genetic markers (the barcoding region of the mitochondrial COI and the ITS region of the nuclear rDNA) to investigate their phylogenetic relationships and to revise their taxonomy. The reconstructed molecular trees confirmed that Alveopora is genetically distant from all poritid genera but closely related to the family Acroporidae, whereas the other genera are genetically closely related. The molecular trees also revealed that Machadoporites and Poritipora were indistinguishable from Goniopora. However, Goniopora stutchburyi was genetically isolated from the other congeneric species and formed a sister group to Goniopora together with Porites and Stylaraea, thus suggesting that 24 septa could be an ancestral feature in the Poritidae. Based on these data, we move G. stutchburyi into a new genus, Bernardpora gen. nov., whereas Machadoporites and Poritipora are merged with Goniopora.     

The evolution of floral nectaries in Disa (Orchidaceae: Disinae): recapitulation or diversifying innovation?

Background and Aims

The Orchidaceae have a history of recurring convergent evolution in floral function as nectar production has evolved repeatedly from an ancestral nectarless state. However, orchids exhibit considerable diversity in nectary type, position and morphology, indicating that this convergence arose from alternative adaptive solutions. Using the genus Disa, this study asks whether repeated evolution of floral nectaries involved recapitulation of the same nectary type or diversifying innovation. Epidermis morphology of closely related nectar-producing and nectarless species is also compared in order to identify histological changes that accompanied the gain or loss of nectar production.

Methods

The micromorphology of nectaries and positionally equivalent tissues in nectarless species was examined with light and scanning electron microscopy. This information was subjected to phylogenetic analyses to reconstruct nectary evolution and compare characteristics of nectar-producing and nectarless species.

Key Results

Two nectary types evolved in Disa. Nectar exudation by modified stomata in floral spurs evolved twice, whereas exudation by a secretory epidermis evolved six times in different perianth segments. The spur epidermis of nectarless species exhibited considerable micromorphological variation, including strongly textured surfaces and non-secreting stomata in some species. Epidermis morphology of nectar-producing species did not differ consistently from that of rewardless species at the magnifications used in this study, suggesting that transitions from rewardlessness to nectar production are not necessarily accompanied by visible morphological changes but only require sub-cellular modification.

Conclusions

Independent nectary evolution in Disa involved both repeated recapitulation of secretory epidermis, which is present in the sister genus Brownleea, and innovation of stomatal nectaries. These contrasting nectary types and positional diversity within types imply weak genetic, developmental or physiological constraints in ancestral, nectarless Disa. Such functional convergence generated by morphologically diverse solutions probably also underlies the extensive diversity of nectary types and positions in the Orchidaceae.     

Investigation of nuclear and mitochondrial DNA polymorphism in closely related species of endemic Baikal sponges

In order to investigate the phylogenetic relationships among endemic Baikal sponges of the family Lubomirskiidae and to clarify their taxonomy, the sequence variation at the silicatein-encoding gene and the mtDNA intergenic region was examined. Phylogenetic analysis of the silicatein α1 gene exonic regions in six freshwater sponge species revealed considerable interspecific variability of this region. The analysis performed did not support the monophyly of the genera Lubomirskia and Baikalospongia. The mtDNA region between the COX2 and ATP6 genes was examined in five species from the Lubomirskiidae family, including multiple samples for analyzing intraspecific variations. According to the data obtained, the genus Baikalospongia was paraphyletic with respect to Lubomirskia, while B. bacilifera and B. recta did not form monophyletic groups. Molecular data indicate that taxonomy of Lubomirskiidae should be revised. It was demonstrated that, in endemic Baikal sponges, the accelerated evolution was accompanied by an increase in the length of the non-coding regions in both mitochondrial and nuclear genes.     

Taxonomic study of spongy spumellarian Radiolaria with three and four coplanar spines or arms from the middle Carnian (Late Triassic) of the Köseyahya nappe (Elbistan, SE Turkey) and other Triassic localities

The present article is a taxonomic study of all spongy spumellarian radiolarian taxa with three and four coplanar spines or spongy arms occurring in the middle Carnian from the Köseyahya section, near the town of Elbistan, SE Turkey. This fauna is characteristic of the Tetraporobrachia haeckeli radiolarian Zone, and comes from an 8 m thick succession of clayey-cherty limestones occurring at the lower part of the section. In addition, a few species from the Middle and Upper Triassic from other areas have been also included in this study to improve some generic diagnoses, and to better comprehend the diversity and evolutionary trends of some genera, subfamilies and families. The taxonomy at the generic and suprageneric levels is based primarily on the types of microsphere. This new approach allowed new taxonomic arrangements of genera and suprageneric units, and suggested new phylogenetic relationships among these radiolarians and between them and younger radiolarians. The authors discuss and describe 69 species, of which 37 are new, and 14 genera, of which three are new (Paraparonaella, Pseudangulobracchia, and Ropanaella). The genus Triassoastrum and others are reinterpreted. All genera studied are assigned to five subfamilies, of which two are new (Tetrapaurinellinae and Triassocrucellinae), and two families (Tritrabidae and Veghicycliidae). Nine species in open nomenclature are also illustrated.     

The impact of epicuticular wax on gas-exchange and photoinhibition in Leucadendron lanigerum (Proteaceae)

This study investigated the seasonal modification of wax deposition, and the impact of epicuticular wax on gas-exchange as well as photoinhibition in Leucadendron lanigerum, a species from the Proteaceae family with wax-covered leaf surfaces and the stomata also partially occluded by wax. The results of this study demonstrated that the deposition of epicuticular wax in L. lanigerum is dependent on the age of the leaf as well as the season, and generation and regeneration of wax occur mostly in spring while transformation and also degeneration of wax crystals occur in winter. Epicuticular waxes decreased cuticular water loss, but had little impact on leaf reflectance. The temperature of leaves without wax was lower than that of wax-covered leaves, indicating that the rate of transpiration impacted more on leaf temperature than reflectance of light in the PAR range in L. lanigerum. The wax coverage at the entrance of stomata in L. lanigerum increased resistance to gas diffusion and as a consequence decreased stomatal conductance, transpiration and photosynthesis. Also, the results indicated that epicuticular waxes do help prevent photodamage in L. lanigerum, and so this property could benefit plants living in arid environments with high solar radiation.