Style curvature and its adaptive significance in the Malvaceae

Curvature of un-pollinated styles towards the anthers in the Malvaceae has been interpreted as different adaptive mechanisms, presenting a challenging problem for evolutionary biologists. We have surveyed different species of this family to determine in which style curvature occurs, and to determine its possible functional roles. Two distinct types of style curvature occur in 18 species distributed in eight genera of four tribes: Type I, before pollen shedding, occurs in species of the Malvavisceae, Ureneae, and Hibisceae tribes, which have highly receptive stigmas and viable pollen when curvature brings stigmas into contact with anthers; and Type II, after pollen shedding, only appears in the protandrous species of the Malveae tribe. Curvature is often associated with annual and perennial herbs. We conclude that the adaptive significance of style curvature in the Malvaceae includes delayed selfing, promotion of outcrossing, and reduction in intrafloral male–female interference, even if the frequency of two or three of these occurs in one species only. This diversity provides model plants and the opportunity for determining the evolution, relative importance, and harmony mechanism of different adaptive significance, especially when two or three functions occur simultaneously in one floral movement of one species (e.g., Kosteletzkya virginica).     

Pollen wall development in Malvastrum corchorifolium (Malvaceae)

The Malvaceae family has many species that are the subject of systematic controversy. Its broad spectrum of fruit and pollen morphology has challenged taxonomists because often morphological studies lead to different conclusions. Therefore, this study of selected stages of pollen wall development in Malvastrum corchorifolium is offered as another approach to verify its current taxonomic assignment and assist in the clarification of malvacean ancestry. Aperture number, endexine thickness and the presence of basal cushions are features that concur with its present placement in the Abutileae tribe, Sidinae subtribe and genus Malvastrum. Its advanced spine morphology, long spines with pointed apices and prominent basal cushions, suggest that Malvastrum corchorifolium is highly specialized and evolutionarily advanced.     

COMPARATIVE ANATOMY OF CHAROPHYTA: II. THE AXIAL NODAL COMPLEX—AN APPROACH TO THE TAXONOMY OF LAMPROTHAMNIUM12

The present investigation on the axial nodes of 32 taxa belonging to the genera Chara, Lamprothamnium, Nitellopsis, Nitella and Tolypella confirms previous reports that within a given taxonomic group the structure of the main axial nodal complex is highly consistent. Besides the genera Nitella and Tolypella of the tribe Nitelleae, Lamprothamnium of the tribe Chareae is the only genus in which the central cells of the main axial nodal complex subdivide. This anatomical feature of the main axial nodal complex thus clearly separates the genus Lamprothamnium from the other genera of the tribe chareae. In 2 controversial species of the genus Chara, C. hornemannii and C. buckellii, the present study reveals that the central cells of their main axial nodal complexes do not subdivide. The transfer of these two species to the genus Lamprothamnium by Daily (1) may not be appropriate.     

INVESTIGATIONS OF ANGIOSPERMS FROM THE EOCENE OF NORTH AMERICA: RHAMNUS MARGINATUS (RHAMNACEAE) REEXAMINED

Leaf compressions, previously assigned to Rhamnus marginatus Lesquereux, were collected from the Middle Eocene Claiborne Formation of western Kentucky and Tennessee. The leaf architecture and cuticular features of over 40 compressions were carefully examined and compared to those of many extant species of Rhamnaceae and related families as well as fossil specimens previously assigned to this taxon. This leaf type appears to belong to the Rhamnaceae, however, it conforms more closely to species of several genera in the tribe Zizypheae than to those of Rhamnus or other genera in the tribe Rhamneae. Confident assignment to any specific genus within this complex of genera cannot be made on the basis of leaf characteristics alone and would require discovery and analysis of additional vegetative and reproductive organs. Because this fossil leaf form cannot be confidently assigned to any modern genus and earlier classifications appear to be improper, this leaf type has been reassigned to the taxon Berhamniphyllum claibornense gen. et sp. nov. The transfer of this leaf form at the tribe level reaffirms the need for close examination of taxonomic determinations made by early workers.     

Phylogeny of the core Malvales: evidence from ndhF sequence data

The monophyly of the group comprising the core malvalean families, Bombacaceae, Malvaceae, Sterculiaceae, and Tiliaceae, was recently confirmed by molecular studies, but the internal structure of this clade is poorly understood. In this study, we examined sequences of the chloroplast ndhF gene (aligned length 2226 bp) from 70 exemplars representing 35 of the 39 putative tribes of core Malvales. The monophyly of one traditional family, the Malvaceae, was supported in the trees resulting from these data, but the other three families, as traditionally circumscribed, are nonmonophyletic. In addition, the following relationships were well supported: (1) a clade, /Malvatheca, consisting of traditional Malvaceae and Bombacaceae (except some members of tribe Durioneae), plus Fremontodendron and Chiranthodendron, which are usually treated as Sterculiaceae; (2) a clade, /Malvadendrina, supported by a unique 21-bp (base pair) deletion and consisting of /Malvatheca, plus five additional subclades, including representatives of Sterculiaceae and Tiliaceae, and Durionieae; (3) a clade, /Byttneriina, with genera traditionally assigned to several tribes of Tiliaceae, plus exemplars of tribes Byttnerieae, Hermannieae, and Lasiopetaleae of Sterculiaceae. The most striking departures from traditional classifications are the following: Durio and relatives appear to be more closely related to Helicteres and Reevesia (Sterculiaceae) than to Bombacaceae; several genera traditionally considered as Bombacaceae (Camptostemon, Matisia, Phragmotheca, and Quararibea) or Sterculiaceae (Chiranthodendron and Fremontodendron) appear as sister lineages to the traditional Malvaceae; the traditional tribe Helictereae (Sterculiaceae) is polyphyletic; and Sterculiaceae and Tiliaceae, as traditionally circumscribed, represent polyphyletic groups that cannot sensibly be maintained with their traditional limits for purposes of classification. We discuss morphological characters and conclude that there has been extensive homoplasy in characters previously used to delineate major taxonomic groups in core Malvales. The topologies here also suggest that /Malvatheca do not have as a synapormophy monothecate anthers, as has been previously supposed but, instead, may be united by dithecate, transversely septate (polysporangiate) anthers, as found in basal members of both /Bombacoideae and /Malvoideae. Thus, “monothecate” anthers may have been derived at least twice, independently, within the /Bombacoideae (core Bombacaceae) and /Malvoideae (traditional Malvaceae).     

ANATOMY OF THE GYNOECIUM IN TWO SPECIES OF BAKERIDESIA (MALVACEAE)

Structure of the gynoecium is described in two species of Bakeridesia, subgenus Bakeridesia (Malvaceae, tribe Malveae). The dorsal wall of each carpel bears a winglike projection with a marginal pair of pubescent, bluntly dentate wings. The projection arises as a single, solid ridge of tissue after the ovules are initiated and after the ventral carpellary margins are fused with the receptacle. Two multiseriate layers of fiber-sclereids line each locule and continue into the winglike projection where they are separated by parenchyma. Gynoecial vascularization is described in detail. The richly vascularized carpels are supplied by five traces: a median dorsal trace, which bifurcates into two dorsal bundles; two lateral traces; and two ventral traces. Adjacent ventral traces, lateral traces, and septal bundles are fused—i.e., they are held in common by neighboring carpels. The presence of lateral carpellary traces may be a primitive character in the tribe Malveae.     

Bobgunnia, a new African genus of tribe Swartzieae (Fabaceae, Faboideae)

A new genus, Bobgunnia, is established in tribe Swartzieae for the African species of Swartzia. Two new combinations are made: B. fistuloides and B. madagascariensis. The new genus has seeds, unlike the remainder of tribe Swartzieae but like the other tribes of Faboideae. The systematic position of Swartzieae is reevaluated.     

POLLEN MORPHOLOGY OF THE TRIBE SWARTZIEAE (SUBFAMILY PAPILIONOIDEAE: LEGUMINOSAE). 1. INTRODUCTION AND ALL GENERA EXCLUDING ALDINA AND SWARTZIA

The pollen morphology of 9 of the 11 genera of the tribe Swartzieae is described together with that of Holocalyx and Cyathostegia, two genera recently removed from the tribe based on macromorphology. The pollen is small, spheroidal to subprolate, primarily tricolporate with a perforate tectum and generally typical of the Leguminosae. Nonetheless, many of the genera have distinctive pollen morphology. Baphiopsis is 6-colporate. The genera Harleyodendron, Lecointea and one species of Exostyles have supratectal spinules. Bocoa viridiflora has striate/rugulate ornamentation very distinct from the other species of the genus Bocoa. The exine stratification is varied but Candolleodendron has a very thick endexine and narrow foot layer. The pollen of African taxa does not differ significantly from that of South American taxa. Pollen morphology does not clarify the taxonomic relationships of the tribe and provides little evidence to assist in positioning Holocalyx and Cyathostegia.     

Phylogenetics,delimitation and historical biogeography of the pantropical tree genus Thespesia (Malvaceae,Gossypieae)

Thespesia consists of 16 species of trees and shrubs from Southeast Asia–Oceania, Africa and America, the most well known being T. populnea, a small tree of tropical coastal areas around the world. Phylogenetic relationships in the genus and among its allies in tribe Gossypieae were inferred using three plastid and two nuclear regions to ascertain its generic delimitation and explore its biogeographical history. Maximum‐likelihood and Bayesian analyses confirmed that Thespesia is not monophyletic and, based on these results, Azanza is reinstated to accommodate the two species previously placed in Thespesia section Lampas. Dating analyses and ancestral range estimation indicated that Thespesia s.s. most likely originated in Southeast Asia–Oceania c. 30 Mya, but extant species did not begin to differentiate until the late Miocene. Two dispersal events, one into Africa c. 11 Mya and another into America (Antilles) c. 9 Mya, gave rise to the African and the Greater Antillean endemics, respectively. The two most widespread hydrochorous species, T. populnea and T. populneoides, originated in Southeast Asia–Oceania from where they spread to other parts of the world. Our analysis also indicated a much earlier origin than previously reported for the eumalvoid clade and its tribes Gossypieae, Malveae and Hibisceae suggesting that vicariance might have had an important role early in the history of these groups.     

Molecular phylogeny and the time of divergence of minges (Chironomidae,Nematocera, Diptera) inferred from a partial nucleotide sequence of the cytochrome oxidase I gene (<Emphasis Type="Italic">COI</Emphasis>)

This is the first study to infer the phylogenetic structure of minges of the subfamily Chironominae from the amino acid sequence of cytochrome oxidase I (COI). The subdivision of Chironominae into two tribes, Chironomini and Tanytarsini, has been confirmed. The segregation of the genera Pseudochironomus and Riethia into a separate tribe has not been confirmed. Stenochironomus gibbus forms a branch considerably deviating from the subfamily Chironominae. The genus Micropsectra is formed by a large polyphyletic cluster that also includes the genera Virgotanytharsus, Reotanytharsus, Kenopsectra, and Parapsectra. Tanytarsus is the basal genus of the tribe Tanytarsini. The times of divergence of the main taxa of Chironominae have been estimated. The calculated time of divergence of the genus Chironomus disproves the assumption that it is phylogenetically old.     

缘蝽科的比较形态学研究Ⅲ（异翅亚目：缘蝽总科）

缘蝽科的比较形态学研究　Ⅲ（异翅亚目：缘蝽总科）李新正（中国科学院海洋研究所青岛２６６０７１）１５棒缘蝽亚科（Ｐｓｅｕｄｏｐｈｌｏｅｉｎａｅ）（图６８—８３）棒缘蝽类包括２８个属,除ＶｉｌｇａＳｔａｌ为新世界分布,ＣｅｒａｌｅｐｔｕｓＣｏｓｔａ和颗缘...     

THE MORPHOLOGY AND RELATIONSHIPS OF DALECHAMPIA SCANDENS (EUPHORBIACEAE)

The circumtropical but preponderantly American genus Dalechampia, comprising nearly 100 species of twining vines (or rarely subshrubs), is strikingly isolated within the Euphorbiaceae because of its distinctive bibracteate inflorescences. There has been considerable taxonomic controversy with regard to the relationships of the genus, and it has been suggested that Dalechampia is allied to the tribe Euphorbieae because of a supposed analogy between its inflorescence and the cyathium in the Euphorbieae. Field and laboratory investigations of the common American species D. scandens, together with a comparative survey of related species, have thrown some light on these problems. The Dalechampia inflorescence seems best interpreted as consisting of a terminal staminate pleiochasium (with part of the lateral branches transformed for nectar production), juxtaposed to a 3-flowered pistillate cyme. The lips of the conspicuous bilabiate involucre are formed by the hypertrophied bracts which subtend the staminate and pistillate cymes. The bisexual inflorescences appear to be distinctly proterogynous, rather than proterandrous, as has been previously suggested. The configuration of the inflorescence—a bilaterally symmetrical pseudanthium—suggests adaptation for crosspollination, but the closing movement of the bracts makes self-pollination probable in the absence of visits by pollinators. The similarity of the Dalechampia inflorescence to the cyathium of the Euphorbieae appears to be entirely superficial, and both reproductive and vegetative data suggest that Dalechampia is related to taxa of tribe Plukenetieae.     

MORPHOLOGY,EVOLUTION, AND TAXONOMIC SIGNIFICANCE OF THE INFLORESCENCE IN CORDYLANTHUS (SCROPHULARIACEAE)

The genus Cordyhmthus has considerable diversity in its inflorescences while the other genera of tribe Rhinantheae (Scrophulariaceae) uniformly have racemes or spikes. Four distinct inflorescence types are recognized and their homologies and evolutionary history are postulated. Thus it is suggested that the basic florescence type, the elongated spike (Type I), has undergone evolutionary reduction to a few-flowered spike and ultimately to a single-flowered florescence (Type II). Further evolution involving processes of compaction and clustering of the single-flowered florescences has resulted in glomerulate clusters (Type III) and spiciform clusters (Type IV). Knowledge of inflorescence homologies and distribution of the four inflorescence types in the genus has been of considerable aid in formulating a new infrageneric classification. Using evidence primarily from inflorescence, floral, and seed morphology, as well as from geographical distribution and ecology, a classification is proposed establishing three subgenera, namely subg. Dicranostegia, subg. Hemistegia, and subg. Cordylanthus, the last with three sections, sect. Cordylanthus, sect. Anisocheila, and sect. Ramosi.     

ON THE POSITION OF THE GENUS KARIMBOLEA (ASCLEPIADACE AE)

The position of the rare and monotypic genus Karimbolea is clarified. Its tribal affinities are examined using mainly floral characters; the former tentative placement in the tribe Asclepiadeae (Asclepiadaceae) is confirmed. Characters of vegetative and floral morphology are used to determine the position of the genus within the tribe Asclepiadeae. Sarcostemma is identified as the most likely sister taxon of Karimbolea. Triterpenoid data obtained from gas-liquid chromatographic analysis of latex are used to test this hypothesis. This paper forms the first study within the Asclepiadaceae using two independent data sets to clarify the position of a taxon of uncertain affinities.     

PHYLOGENY OF THE TRIBE CERATAPHIDINI (HOMOPTERA) AND THE EVOLUTION OF THE HORNED SOLDIER APHIDS

The horned soldier aphids of the Cerataphidini, unlike most social insects that reside in nests, live on the open surface of plants. The lack of a nest and other obvious ecological correlates makes it unclear why secondary-host soldiers might have evolved. Here I present a molecular phylogenetic analysis of 32 species of the Cerataphidini, including 10 species from the genera Ceratovacuna and Pseudoregma that produce horned soldiers. The phylogeny suggests that horned soldiers evolved once and were lost once or twice. Most horned soldiers are a morphologically specialized caste and two species that have unspecialized soldiers are independently derived from species with specialized castes. The genus Ceratovacuna appears to have undergone a relatively rapid radiation. Mapping secondary-host plants and geographic ranges onto the phylogeny suggests that bamboos were the ancestral secondary-host plants and that the Asian tropics and subtropics were the ancestral geographic regions for the genera Astegopteryx, Ceratoglyphina, Ceratovacuna Chaitoregma, and Pseudoregma and possibly for the entire tribe. There is evidence for vicariant events that separate the tropical and subtropical lineages in all of the major lineages of the tribe and for dispersal of some lineages. Based on these results, I present hypotheses for the causes and consequences of horned-soldier evolution.     

First mesozoic representative of the subfamily tenebrioninae (Coleoptera,Tenebrionidae) from the lower cretaceous of Yixian (China,Liaoning)

A new genus and a new species of the tenebrionine tribe Alphitobiini, Alphitopsis initialis gen. et sp. nov. is described from Yixian (Liaoning Province, China). The new genus is the oldest member of the subfamily Tenebrioninae and it is most similar to Metaclisa Jacquelin du Val, 1861, but differs from all the genera of the tribe Alphitobiini in the structure of elytral epipleura and antennae.     

The genus hampea(Malvaceae)

The genusHampea Schlecht. is included in the Malvaceae, tribe Gossypieae, rather than in the Bombacaceae where it was originally placed. Discussion includes the morphology, geography (central Mexico to western Colombia), reproductive cycle, utilization and vernacular names, and cytology (n = 13) of the genus. Three species have perfect flowers; the remainder are dioecious. The 16 species (and one variety) that are accepted are divided into three sections, one of which is further subdivided into three series. The following taxa are described as new:H. nutricia, H. mexicana, H. sphaerocarpa, andH. appendiculata var.longicalyx.     

Testing the monophyly and position of the North American shrubby desert genus Leucophyllum (Scrophulariaceae: Leucophylleae)

Leucophyllum is one of the most remarkable endemic genera of North American deserts, with its simultaneous bloom of showy purple flowers. With Eremogeton and probably Capraria it forms part of tribe Leucophylleae. Leucophyllum has 16 species distributed mostly throughout the Chihuahuan and Tehuacán deserts. The three genera were sampled to investigate the phylogenetic relationships among them and to test the monophyly of Leucophyllum, based on plastid DNA (trnL‐F, rps16) and nuclear ribosomal (nr)DNA (internal transcribed spacer) sequences. Bayesian inference and maximum‐likelihood analyses confirmed that tribe Leucophylleae is monophyletic and formed by the three Neotropical genera. Separate (plastid DNA and nrDNA) and combined analyses retrieved Leucophyllum as paraphyletic, with L. mojinense as the sister species to the rest of the species in the tribe and Capraria spp. nested in one of two clades of Leucophyllum. Further monographic work is needed to identify the defining characters and limits of the genera, but we suggest that L. mojinense, with its different vegetative architecture, distinctive flowers and dissimilar distribution could be placed in its own genus. Each of the two clades in Leucophyllum could be considered a genus in its own right, and Capraria and Eremogeton can be recognized as independent genera, as they are at present. Leucophyllum ambiguum, the type species of the genus, belongs to one of the clades so the species of the other could be considered members of a new genus. The only diagnostic character detected at present is a ventricose corolla tube in one of the clades in Leucophyllum and a pressed corolla tube in the other. © 2013 The Linnean Society of London     

铃兰族rbcL基因的PCR—RFLP分析

本文用7属9种铃兰族Tribe convallarieae植物的叶绿体DNA中rbcL基因片段的PCR产物的RFLP结果进行聚类分析。结果表明:开口箭属与蜘蛛抱蛋属关系密切,夏须草属与族内其余各属亲缘关系稍远,与外部器官形态、核型和孢粉学资料所得出的结论基本一致。此外,本文对铃兰属的系统位置也进行了讨论。