Chloroplast DNA variation in the cultivated and wild olive taxa of the genus Olea L.

Polymorphism in the lengths of restriction fragments of the whole cpDNA molecule were studied in 15 taxa (species or subspecies) of the genus Olea. From restriction analysis using nine endonucleases, 28 site mutations and five length polymorphisms were identified, corresponding to 12 distinct chlorotypes. From a phenetic analysis based on a Nei’s dissimilarity matrix and a Dollo parsimony cladistic analysis using, as an outgroup, a species of the genus Phillyrea close to Olea, the ten taxa of section Olea were distinguished clearly from the five taxa of section Ligustroides which appear to posses more ancestral cpDNA variants. Within the section Ligustroides, the tropical species from central-western Africa, Olea hochtetteri, showed a chlorotype which differed substantially from those of the other four Olea taxa growing in southern Africa, supporting a previous assessment according to which O. hochtetteri may have been subjected to a long period of geographical isolation from the other Olea taxa. Within the Olea section, three phyla were identified corresponding to South and East Africa taxa, Asiatic taxa, and a group including Saharan, Macaronesian and Mediteranean taxa, respectively. On the basis of cpDNA variation, the closest Olea taxa to the single Mediterranean species, Olea europaea, represented by its very predominant chlorotype, observed in both wild and cultivated olive, were found to be Olea laperrinei (from the Sahara), Olea maroccana (from Maroccan High Atlas) and Olea cerasiformis (from Macaronesia). These three taxa, which all share the same chlorotype, may have a common maternal origin. Received: 5 December 1999 / Accepted: 30 December 1999     

Chrysophyceae from freshwater localities near Nijmegen,The Netherlands. II.

Investigations have been carried out on the presence and abundancy of Synuraceae (Chrysophyceae) in seven freshwater bodies in the neighbourhood of Nijmegen, The Netherlands. Forty-nine taxa have been recorded of which 4 taxa concern first published records from The Netherlands. Two taxa of Mallomonopsis, five taxa of Mallomonas, one taxon of Spiniferomonas and two taxa of Paraphysomonas could not be identified. These taxa may concern undescribed species.Samples taken in April and August revealed a clear preference of most taxa for April at every sampling place, except for Molenwiel. Temperature could be the controlling factor. Most taxa have been found in Geuldert (41) and St. Jansberg (22) both in April. The great difference in the number of taxa at those two sites between both sampling data must be attributed to unusual environmental changes.     

Correction to: An update and reassessment of fern and lycophyte diversity data in the Japanese Archipelago

The fern and lycophyte flora of Japan comprising 721 native taxa (including subspecies and varieties) plus 371 interspecific hybrids was reassessed using a nearly comprehensively sampled distribution map at 10 km resolution vouchered by 216,687 specimens, up-to-date cytotaxonomic information covering 74% of the taxa, and an rbcL sequence dataset covering 97.9% of the taxa. Spatial distribution of species richness and phylogenetic diversity was visualized. Apomixis was observed in 11.0% of the native taxa whose reproductive modes are known. The number of sexually reproducing polyploid taxa (n = 199) is less than sexual diploids (n = 241), and 30 of them are evidently allopolyploid, in contrast with the low number of possible autopolyploids (n = 4). Apomictic taxa were found to have smaller latitudinal ranges than sexual taxa or taxa with multiple reproductive modes. A morphological character dataset in Lucid format is provided for taxonomic identification of the native taxa.

     

Repeated convergent evolution of parthenogenesis in Acariformes (Acari)

The existence of old species‐rich parthenogenetic taxa is a conundrum in evolutionary biology. Such taxa point to ancient parthenogenetic radiations resulting in morphologically distinct species. Ancient parthenogenetic taxa have been proposed to exist in bdelloid rotifers, darwinulid ostracods, and in several taxa of acariform mites (Acariformes, Acari), especially in oribatid mites (Oribatida, Acari). Here, we investigate the diversification of Acariformes and their ancestral mode of reproduction using 18S rRNA. Because parthenogenetic taxa tend to be more frequent in phylogenetically old taxa of Acariformes, we sequenced a wide range of members of this taxon, including early‐derivative taxa of Prostigmata, Astigmata, Endeostigmata, and Oribatida. Ancestral character state reconstruction indicated that (a) Acariformes as well as Oribatida evolved from a sexual ancestor, (b) the primary mode of reproduction during evolution of Acariformes was sexual; however, species‐rich parthenogenetic taxa radiated independently at least four times (in Brachychthonioidea (Oribatida), Enarthronota (Oribatida), and twice in Nothrina (Oribatida), (c) parthenogenesis additionally evolved frequently in species‐poor taxa, for example, Tectocepheus, Oppiella, Rostrozetes, Limnozetes, and Atropacarus, and (d) sexual reproduction likely re‐evolved at least three times from species‐rich parthenogenetic clusters, in Crotonia (Nothrina), in Mesoplophora/Apoplophora (Mesoplophoridae, Enarthronota), and in Sphaerochthonius/Prototritia (Protoplophoridae, Enarthronota). We discuss possible reasons that favored the frequent diversification of parthenogenetic taxa including the continuous long‐term availability of dead organic matter resources as well as generalist feeding of species as indicated by natural variations in stable isotope ratios.     

Molecular taxonomy of Vicia ser. Vicia based on Amplified Fragment Length Polymorphisms

 Amplified Fragment Length Polymorphisms (AFLPs) were used to study the taxonomic relationships in Vicia ser. Vicia. 109 accessions representing the taxa and distribution in the series were evaluated using two primer combinations in an attempt to clarify its taxonomy. The study concludes that four species exist in the series. Vicia incisa should be considered as a separate taxon and does not belong to the Vicia sativa aggregate. Within the series Vicia pyrenaica appears to be the most closely related to the Vicia sativa aggregate. Within the aggregate 6 taxa can be recognised. They are very closely related and for none of the taxa in the aggregate is there a taxon-specific absence or presence of AFLP bands. We consider these taxa to be subspecies. Several accessions belonging to the aggregate were found which could not be placed within one of the taxa and are most likely the products of mutations or hybridisation between taxa. Received March 12, 2001 Accepted July 12, 2001     

CHROMOSOME NUMBERS IN SPHAERALCEA SECTION FENDLERIANAE

Chromosome numbers are reported for ten taxa in Sphaeralcea section Fendlerianae (Malvaceae). New ploidy levels are reported for six taxa, with one species not previously reported, and extensive polyploidy at all taxonomic levels is documented. The geographic and taxonomic distribution of polyploids suggests that polyploidy arose many times in the taxa of Sphaeralcea. Sphaeralcea fendleri var. venusta, S. polychroma, and S. wrightii populations have yielded exclusively tetraploid counts. Tetraploidy is correlated with taxa having lavender petals. Polyploidy has also allowed the taxa to expand their distributions without resulting in speciation.     

Musci Austro-Africana III. Alpine mosses of Lesotho

Abstract

The ecology in western Norway of twelve taxa within the moss genus Andreaea has been investigated. Taxon abundances along environmental. gradients were recorded in 568 sample units. Numerical methods were used to estimate the realized niches of each taxon separately by regression analyses, and the realized niches for all the taxa simultaneously by constrained ordination.

The genus Andreaea is restricted to hard rocks with a low calcium ‘concentration, although it can also grow on mildly basic rock types. In addition, lithosols and phyllite are alternative substrates at high altitudes.

The main environmental factor differentiating between the niches of the Andreaea taxa is moisture, although the taxa are separated more along the altitudinal gradient. A general trend for Andreaea taxa is an interaction between moisture-controlling environmental factors; a low degree of flushing correlates with a high degree of shelter or cracks, or with low radiation. At high altitudes snow-persistence interacts with the moisture gradient. Taxa normally occurring in late snow-beds receive less water from sources other than snow-melt, whereas taxa occurring in sites free of snow early have a wider range of water sources. The second major environmental factor for niche differentiation is chemistry, namely soil pH. However, all taxa occur in sites with low values for soil pH. Other environmental factors mainly differentiate between pairs of taxa: hard rock — lithosols (A. rupestris var. rupestris — A. alpestris), degree of slope (A. rothii ssp. falcata — A. rothii ssp. rothii), and number of cracks (A. rothii s.1. — A. megistospora ssp. megistospora). All Andreaea taxa found within the study area are ecologically distinct in relation to one or more environmental factor. The ecological difference between A. rupestris var. rupestris and A. alpestris is, however, weak within the study area.

In general, taxa with a wide morphological variability have a wide ecological tolerance and a wide geographical and altitudinal distribution. Explanation of distributional patterns at different spatial scales requires consideration of the dispersal strategies.

Taxa that are regarded as pleisomorphous tend to occur in sites experiencing high humidity (A. nivalis, A. frigida), whereas there is a dominant trend towards a higher drought tolerance in apomorphous taxa (A. rothii s.1., A. megistospora ssp. megistospora, A. rupestris s.1.). A. blyttii is a special case, probably with an early departure from the other taxa in section Nerviae. It grows mainly in late or extremely late snow-beds. Within the section Andreaea, forms of A. obovata show some signs of ecological convergence towards pleisotypic ecology (flood-zone habitats), although A. obovata favours an intermediate humidity. A. alpina, a lowland taxon favouring high humidity, probably separated early from other taxa in this section.     

Higher-level systematics of Acanthaceae determined by chloroplast DNA sequences

Parsimony analyses of ndhF chloroplast gene sequences were undertaken for 15 species of Acanthaceae and nine representative outgroup species. In addition, parsimony analyses of rbcL sequences were undertaken for 12 species of Acanthaceae and the same nine outgroup species as for ndhF. The results indicate that ndhF provides more informative characters and greater systematic resolution at this hierarchical level than rbcL. The ndhF analyses demonstrate that Elytraria and Thunbergia are successive sister taxa to all Acanthaceae taxa that have retinacula and explosive fruits. These data also demonstrate that taxa with both retinacula and explosive fruits can be subdivided further into two monophyletic groups that correspond to taxa with and without cystoliths. Within the group with cystoliths three putatively monophyletic groups correspond to taxa possessing quincuncial, left contort, and ascending-cochlear corolla aestivation patterns. The results of the rbcL analysis provide less systematic resolution than ndhF but do contain several congruent arrangements of taxa within Acanthaceae.     

Achene anatomy and stomatal characteristics of eighteen Crepis L. (Asteraceae) taxa from Turkey with notes on their systematic significance

Achene anatomy and stomatal characteristics of eighteen Crepis taxa from Turkey are here described for the first time. In all taxa examined the pericarp is composed of several layers of sclerenchymatous and parenchymatous cells. As for the achene, differences among taxa mainly concern the pericarp structure and its thickness and width. Stomata are present on both surface of the leaf in all studied taxa and all taxa have anomocytic type stomata. However, the dimensions (length and width) and density of the stomata differ significantly among the studied taxa. In addition, the dimensions of stomata are negatively correlated with stomata density. It is concluded that achene anatomy and stomatal characteristics are useful for delimitation of Crepis taxa and a key to taxa based on these characters is provided. However, based on achene anatomy and stomatal characteristics, we found no argument for an exclusion of the Lagoseris group from Crepis as has previously been proposed.     

Low genetic variation of invasive Fallopia spp. in their northernmost European distribution range

Knowledge about the reproduction strategies of invasive species is fundamental for effective control. The invasive Fallopia taxa (Japanese knotweed s.l.) reproduce mainly clonally in Europe, and preventing spread of vegetative fragments is the most important control measure. However, high levels of genetic variation within the hybrid F. × bohemica indicate that hybridization and seed dispersal could be important. In Norway in northern Europe, it is assumed that these taxa do not reproduce sexually due to low temperatures in the autumn when the plants are flowering. The main objective of this study was to examine the genetic variation of invasive Fallopia taxa in selected areas in Norway in order to evaluate whether the taxa may reproduce by seeds in their most northerly distribution range in Europe. Fallopia stands from different localities in Norway were analyzed with respect to prevalence of taxa, and genetic variation within and between taxa was studied using amplified fragment length polymorphism (AFLP). Taxonomic identification based on morphology corresponded with identification based on simple sequence repeats (SSR) and DNA ploidy levels (8× F. japonica, 6× F. × bohemica and 4× F. sachalinensis). No genetic variation within F. japonica was detected. All F. × bohemica samples belonged to a single AFLP genotype, but one sample had a different SSR genotype. Two SSR genotypes of F. sachalinensis were also detected. Extremely low genetic variation within the invasive Fallopia taxa indicates that these taxa do not reproduce sexually in the region, suggesting that control efforts can be focused on preventing clonal spread. Climate warming may increase sexual reproduction of invasive Fallopia taxa in northern regions. The hermaphrodite F. × bohemica is a potential pollen source for the male‐sterile parental species. Targeted eradication of the hybrid can therefore reduce the risk of increased sexual reproduction under future warmer climate.     

Records of chrysophytes with siliceous scales (Mallomonadaceae and Paraphysomonadaceae) from Finnish inland waters

Seventy-three taxa of silica-scaled chrysophytes were found with LM and TEM in 264 samples from 141 Finnish water bodies, including the genera Mallomonas (40 taxa), Synura (9), Chrysosphaerella (3), Spiniferomonas (8) and Paraphysomonas (13). More than half of the taxa are recorded for the first time from Finland and five (Mallomonas actinoloma v. actinoloma, M. favosa, M. mangofera f. gracilis, M. scrobiculata and Spiniferomonas serrata) are new to Europe. Most taxa are illustrated with TEM micrographs and the taxonomy of some interesting species is discussed in detail. The seasonal occurrence of the commonest species is described.     

Revision of Launaea Cass. (Compositae) in Egypt with special references to cypselar diversity

A systematic revision for the species of Launaea Cass. in Egypt has revealed the presence of fourteen taxa belonging to 12 species, of which L. acanthodes (Boiss.) Kuntze is a new recorded. One new combination “L. fragilis subsp. tenuiloba (Boiss.) Zareh & Mohamed” is made. Achene diversity of the studied taxa of Launaea was studied using light and scanning electron microscopy. The taxonomic relationships between the studied taxa were discussed as well as SEM micrographs of achenes are provided. Synonyms and key for the identification of the investigated taxa based on morphological characters as well as notes on distribution are provided.     

CHROMOSOME COUNTS OF COMPOSITAE FROM THE UNITED STATES AND MEXICO

Chromosome counts are reported for 126 taxa representing 122 species and 61 genera of Compositae. First reports include two genera, Stylocline (n = 14) and Chromolepis (n = 19), 17 species, two infraspecific taxa, and one interspecific hybrid. Five additional taxa have chromosome numbers differing from previously published accounts. Carminatia is reinstated to generic status.     

Two new fossil flowers of magnoliid affinity from the Late Cretaceous of New Jersey

Two taxa of cupulate magnoliid fossil flowers, Cronquistiflora and Detrusandra, are described from the Late Cretaceous (Turonian, ∼90 million years before present [MYBP]) Raritan (or lower Magothy) Formation of New Jersey. The fossil taxa are represented by flowers at various stages of development, associated fragments of cup-shaped floral receptacles with attached anthers, and isolated anthers. Both taxa have laminar stamens with adaxial thecae and valvate dehiscence. Pollen is boat-shaped and foveolate in anthers associated with Cronquistiflora and spherical with reticulate ornamentation in Detrusandra. Cup-shaped receptacles are externally bracteose in both taxa. The receptacle of Cronquistiflora is broader than the campanulate one of Detrusandra. Cronquistiflora also has more carpels (∼50 in a spiral vs. ∼5 in a whorl or tight spiral). In Detrusandra the carpels are surrounded by dorsiventrally flattened structures (pistillodes?) that are remote from the attachment of the stamens near the distal rim of the receptacular cupule. Detrusandra stigmas are rounded and bilobed, while those of Cronquistiflora, although bilateral in symmetry, are somewhat peltate. The fossil taxa share prominent characters with extant cupulate magnoliids (e.g., Eupomatia, Calycanthus), but also share characters with other magnoliids including Winteraceae. These fossils represent taxa that are character mosaics relative to currently recognized families. Inclusion of these fossils in existing data matrices and ensuing phylogenetic analyses effect changes in tree topologies consistent with their mosaicism relative to modern taxa. But such analyses do not definitively demonstrate the affinities of the fossils other than illustrating that these fossils are generalized magnoliids. Additional analysis of modern and fossil magnoliids is necessary to fully appreciate the phylogenetic significance and positions of these fossil taxa. However, the results of the phylogenetic analyses do introduce the possibility that extinct taxa of Magnoliales with cupulate floral receptacles were transitional between basal angiosperms and those with tricolpate pollen. The fossils provide insights into the timing of evolution of character complexes now associated with coleopteran pollination.     

Allozyme variation in Japanese species ofChionographis (Liliaceae)

Allozyme variation was examined in three diploid taxaChionographis japonica var.japonica, var.kurokamiana, andC. koidzumiana and three tetraploid taxaC. japonica var.kurohimensis, ssp.hisauchiana, and ssp.minoensis. Results show thatC. japonica var.kurokamiana is genetically closer toC. koidzumiana than to var.japonica. In the tetraploid taxa, fixed heterozygosities were found at several loci, and this supports the hypothesis that these taxa are allotetraploids. Furthermore, the tetraploid taxa have many unique alleles not found in the diploid taxa. This suggests that sufficient time has passed since the origin of tetraploids for new mutations to have been fixed.     

Multifaceted assessment of species validity in the Dasymutilla bioculata species group (Hymenoptera: Mutillidae)

This study examines the validity of the ten species and eight subspecies composing the Dasymutilla bioculata species group. Four lines of evidence are examined: morphological data derived from both sexes; behavioural data derived from the study of mating pairs; geographic distribution; and molecular data derived from the internal transcribed spacers 1 and 2 of the nuclear ribosomal RNA cistron (ITS1 and ITS2). Morphological studies reveal that none of the taxa in question can be consistently diagnosed by any synapomorphies or unique combinations of characters. Mating studies reveal that males of single nominal taxa are attracted to females of multiple nominal taxa, and that females of single nominal taxa attract multiple males. None of the nominal taxa are geographically isolated from the others. Genetic distances between these taxa are significantly lower than those seen in interspecific comparisons of other Dasymutilla species. Based on this evidence, we infer that the taxa in question share a recent common ancestor, and cannot be adequately differentiated using any of the available data sources. Therefore, employing the phylogenetic species concept, Dasymutilla bimaculata Manley & Pitts, Dasymutilla chiron chiron (Blake), Dasymutilla chiron ursula (Cresson), Dasymutilla creusa creusa (Cresson), Dasymutilla creusa bellona (Cresson), Dasymutilla lepeletierii (Fox), Dasymutilla medea (Cresson), Dasymutilla melanippe melanippe Mickel, Dasymutilla melanippe conformis Mickel, Dasymutilla praegrandis praegrandis Mickel, Dasymutilla praegrandis russata Mickel, Dasymutilla pyrrhus (Fox) and Dasymutilla sulcatulla Mickel must be considered junior synonyms of Dasymutilla bioculata (Cresson). We also discuss the identification of this species, as well as subspecific relationships and species‐group implications.     

Effects of water quality and season on diatom community structure in the Damour River,Lebanon

The diatom flora in the lower Damour River, a small coastal river in Lebanon, was studied during 1981. The study area included the Damour estuary and a tributary, the el-Hamam River. Achnanthes minutissima was the most abundant diatom in the flora. Other dominant taxa included Nitzschia dissipata and Navicula cryptocephala var. veneta in the spring and Anomoeoneis vitrea in the fall. The diatom community structure was characterized by 1 or 2 dominant taxa, a few common and many rare taxa, but the taxa in these categories varied according to season and locality. The freshwater flora had a group of 20 taxa which were widely distributed in the study area throughout the study period. These taxa, in addition to a few taxa of more restricted seasonal occurrence, were the major contributers to the flora and are characteristic of this river system. Certain aspects of the flora were resistant to change. Others were more sensitive to environmental conditions. The estuarine flora reflected brackish conditions beginning in June and extending through October.     

Hybridization and polyploidy as drivers of continuing evolution and speciation in Sorbus

Interspecific hybridization and polyploidy are pivotal processes in plant evolution and speciation. The fate of new hybrid and polyploid taxa is determined by their ability to reproduce either sexually or asexually. Hybrids and allopolyploids with odd chromosome numbers are frequently sterile but some establish themselves through asexual reproduction (vegetative or apomixis). This allows novel genotypes to become established by isolating them from gene flow and leads to complex patterns of variation. The genus Sorbus is a good example of taxonomic complexity arising from the combined effects of hybridization, polyploidy and apomixis. The Avon Gorge in South‐west Britain contains the greatest diversity of Sorbus in Europe, with three endemic species and four putative endemic novel hybrids among its 15 native Sorbus taxa. We used a combination of nuclear microsatellite and chloroplast DNA markers to investigate the evolutionary relationships among these Sorbus taxa within the Avon Gorge. We confirm the genetic identity of putative novel taxa and show that hybridization involving sexual diploid species, primarily S. aria and S. torminalis and polyploid facultative apomictic species from subgenus Aria, has been responsible for generating this biodiversity. Importantly our data show that this creative evolutionary process is ongoing within the Avon Gorge. Conservation strategies for the rare endemic Sorbus taxa should therefore consider all Sorbus taxa within the Gorge and must strive to preserve this evolutionary process rather than simply the individual rare taxa that it produces.     

Karyological studies of some representatives of <Emphasis Type="Italic">Tanacetum</Emphasis> L. (Anthemideae-Asteraceae) from north-east Anatolia

The karyotypes of nine Tanacetum taxa distributed in north-east Anatolia, Turkey, were determined and evaluated by cluster analysis and principal-components analysis. Chromosome numbers were 2n = 2x = 18 (8 taxa) and 4x = 36 (1 taxon). Somatic chromosome numbers of two taxa and a new ploidy level in one taxon are reported for the first time. Karyotype analysis indicated that chromosomes of Tanacetum taxa have predominantly median centromeres. The taxa studied differed significantly in the size of the short arms and long arms, and the arm ratio of each pair of homologous chromosomes, indicating structural rearrangements of the chromosomes have been involved in diversification of the taxa. They were placed in 2A, 3A, and 2B of Stebbins’ karyotype classification, showing the presence of a primitive symmetrical karyotype in the genus. Several systematic and evolutionary aspects of the genus are discussed on the basis of karyological data.