bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preliminary DNA fingerprinting of the turf grass <i>Cynodon dactylon</i> (Poaceae: Chloridoideae)
Authors: Roodt R. , Spies J. J. , Burger T. H. 
Published: July 2015

Identification of different cultivars of turf grasses is often very difficult. In a preliminary attempt to identify different cultivars o f Cynodon dactylon (L.) Pers.. random amplified polymorphic DNA (RAPD) analyses of some well-known cultivars used in South Africa, i.e. Bayview. Cape Royal, Florida. Hamsmith. Silverton Blue. Skaapplaas and Titdwart. as well as 10 potential new cultivars, were done. These results were used to determine the genetic distances among cultivars. Only five primers w ere needed to obtain a specific fragment pattern for each cultivar. The degree o f amplification w as used as an additional criterion by including all visible fragments, excluding very faint fragments and only including the brightest fragments. The neighbour-joining trees o f C. dactylon showed best resolution from the data set w ith all visible fragments included. although fragment intensity did not affect the tree topology. The cultivars Silverton Blue and Bayview exhibited the greatest genetic variation and two potential new cultivars were identified. RAPD analyses can. therefore, be used to distin­guish between different C. dactylon cultivars and to determine the genetic variation between them by calculating genetic distances.
A new serotinous species of <i>Cliffortia</i> L. (Rosaceae) from Northern Cape, South Africa and section <i>Arboreae</i> emended
Authors: Fellingham A. C. 
Published: July 2015

A new species. Cliffortia dichotoma Fellingham. from the Oorlogskloof Escarpment, near Nieuwoudtville. Northern Cape, is described and compared to its closest allies in the genus. Cliffortia arborea Marloth. which is widespread along he escarpment of the Great Karoo from Calvinia in the north to Beaufort West in the southeast, and C. conifera E.G.H.OIiv. Fellingham from the Anysberg near Laingsburg. further east in the Karoo. The description of the section Arboreae is emended here to include the new species, and the description of C. aborea is corrected.
Two new species of <i>Romulea</i> (Iridaceae: Crocoideae) from the west­ ern Karoo, Northern Cape and notes on infrageneric classification and range extensions
Authors: Manning J. C. , Goldblatt P. 
Published: July 2015

Two new species of Romulea are described from Northern Cape, raising the number of species in southern Africa to 76. R. collina J.C.Manning Goldblatl is endemic to the Hantamsberg near Calvinia. It is distinguished in subgenus Spatalanthus by its clumped habit, yellow flowers with dark markings in the throat, and short papery bracts. A re-examination of rela­tionships within the subgenus suggests that section Cruciatae is not monophyletic and it is accordingly no longer recog­nized as separate from section Spatalanthus. R. eburnea J.C.Manning Goldblatt is a distinctive species of subgenus Spatalanthus from the Komsberg near Sutherland. It is distinguished by its golden yellow flowers with the apical third of the tepals coloured pale creamy apricot, bracts with broad, translucent margins and tips, and an unusually long perianth tube, 10-13 mm long.
Two new species of Asteraceae from Northern and Western Cape, South Africa and a new synonym
Authors: Manning J. C. , Goldblatt P. 
Published: July 2015

We recognize two new species of Asteraceae from the winter rainfall belt of South Africa and reduce a third to synonomy. Senecio speciosissimus sp. nov. has been confused with S. coleophyllus Turcz. in the past but is distinguished by its taller stature, larger and more finely serrated leaves, and congested synflorescences containing (6-)l 5-40 flowerheads. The two species are also geographically separated: S. speciosissimus occurs in the Hottentots Holland and Franschhoek Mountains of the southwestern Cape, whereas S. coleophyllus is endemic to the Riviersonderend Mountains. Chrysocoma hantamensis sp. nov. is a distinctive new species endemic to the Bokkeveld and Roggeveld Plateaus. It is distinguished by its resprouting habit. 3-5-fid leaves and large capitula, 12-15 mm in diameter, with lanceolate. 3-veined involucral bracts, the largest 9 - 1 0 x 2 mm. Investigation of the variation in leaf morphology of the two radiate species of Oncosiphon, O. africanum (PJ.Bergius) Kallersjo and O. glabratum (Thunb.) Kallersjo. reveals that only one species can be maintained, and O. glabratum is accordingly reduced to synonomy in O. africanum.
Ovule-to-seed development in <i>Dovyalis caffra</i> (Salicaceae: Flacourtieae) with notes on the taxonomic significance of the extranucellar embryo sac
Authors: Steyn E. M. A. , Van Wyk A. E. , Smith G. F. 
Published: July 2015

Dovyalis caffra (Hook.f. Harv.) Hook.f. is a widespread and horticulturally important southern African endemic. Here described, ovule-to-seed development represents the first embryological information on this genus of the tribe Flacourtieae, Salicaceae sensu lato. Results are discussed in the light of data available on the embryology of the order Malpighiales in general and on the tribe Flacourtieae in particular. It is clear that Dovyalis E.Mey. ex Am. shares many characters with other members of the Flacourtieae. Ovules of D. caffra are anatropous. bitegmic and crassinucellate with both bisporic Allium- and monosporic Polygonum-type embryo sacs. One of the most characteristic embryological features of the tribe is the pres­ence of an unusual, extranucellar embryo sac that stretches halfway up into the micropyle. Since this extraordinary-shaped embryo sac also defines the embryo sacs of Salix L. and Populus L., it is suggested that the character provides strong sup­port for the proposed close phylogenetic link between tribes Flacourtieae and Saliceae of Salicaceae sensu lato.
Two new species of <i>Nemesia</i> (Scrophulariaceae) from southern Africa
Authors: Steiner K. E. 
Published: July 2015

Two new annual species of Nemesia Vent, are described from southern Africa. N. williamsonii is characterized by bright orange flowers with an inflated yellow palate. It differs from the related N. maxii Hiern by having a spur that projects backwards, not downwards, and bracts that are lanceolate with a truncate base, not triangular or cordate. It is unusual for the genus in having dimorphic seeds. N. williamsonii occurs almost exclusively in the Richtersveld. but has been collected in a few localities across the Orange River in southern Namibia. N. hemiptera is a delicate, wiry-stemmed annual with small white flowers. The flowers are characterized by a tiny nipple-like spur and a seed that is winged on onlv one side. N. hemiptera isendemic to the Kamiesberg from near Garies to Kamieskroon.
Notes on the systematics and nomenclature of <i>Tritonia</i> (Iridaceae: Crocoideae)
Authors: Goldblatt P. , Manning J. C. 
Published: July 2015

Study of some early types of species now known to belong to the genus Tritonia Ker Gaw l.. a member of Iridaceae. sub­family Crocoideae, comprising some 28 species of southern and south tropical Africa, has shown the need for some nomen- clatural adjustments. Ixia undulata Burm.f. (1768) is an earlier name for T. crispa (L.f.) Ker Gawl. based on Gladiolus crispus L.f. (1782) and the combination T. undulata (Burm.f.) Baker must be used for the species, which is native to the western half of Western Cape, South Africa. The variety T. crispa var. parx iflora is also reduced to synonymy. The type specimen of Ixia gladiolaris Lam. (1789), currently considered a synonym of Tritonia securigera (Aiton) Ker Gawl.. has flowers that lack the characteristic tooth-like ridges on the lower tepals of the latter, and corresponds closely to the eastern southern African T. lineata (Salisb.) Ker Gawl., based on Gladiolus lineatus Salisb. (1796). The new combination T. gladiolaris (Lam.) Goldblatt J.C. Manning is made and T. lineata is reduced to synonymy. Montbretia lacerata and Tritonia lacerata. erroneously regarded as synonyms of T. crispa, are combinations based on Gladiolus laceratus Burm.f., a species that remains unidenti­fied because no type is known and the description is too vague to permit its identification. Lastly, field studies have shown that the cnsped-leaved T. watermeveri is connected by a series of morphological intermediates to typical T. securigera. which has straight leaves and identical flowers. The new combination T. securigera subsp. watermeveri (L.Bolus) J.C.Manning Goldblatt is proposed for this taxon.
New species and notes on the genus <i>Cliffortia</i> (Rosaceae)
Authors: Whitehouse C. M. , Fellingman A. C. 
Published: July 2015

Seven new species of Cliffortia L. endemic to the Cape Floristic Region (CFR) are described. C. anthospermoides. C. cruciata. C. ferricola, C. gracillima. C. perpendicularis. C. sparsa and C. weimarckii. A further species from the Graaff- Reinet area, described by Weimarck but not formally named, is here given the name C. bolusii. New varieties C cuneata var. cylindrica and C.filifolia var arenaria are also described, and C. gracilis Harv. is recombined as C. dentata var. gracilis. Cliffortia discolor Weim. and C. hermaphroditica Weim. are reduced to synonyms of C. odorata L.f. and C. juniperina L.f. respectively. There are now 132 species recognized in Cliffortia, 124 of which are found in the CFR and 109 endemic to the region.
Systematics of the southern African genus Ixia (Iridaceae). 1. The <i>I.</i> <i>rapunculoides</i> complex
Authors: Goldblatt P. , Manning J. C. 
Published: July 2015

Field and laboratory investigation of the six varieties of Ixia rapunculoides Delile (recognized in the current revisions and flora accounts of this southern African genus of some 65 species) show that a revised taxonomy better reflects the biology of the complex. The complex is defined by the funnel-shaped perianth tube, filaments fully and anthers partly included in the perianth tube. Our conclusions indicate that I. rapunculoides (currently var. rapunculoides) is restricted to the western Karoo and has broad, leathery leaves, a short perianth tube, mostly 5.5-8.0 mm long, and half nodding blue-mauve flowers. Plants currently referred to I. rapunculoides var. flaccida G.J.Lewis, include four sets of populations that we regard as two separate species. These are: I. flaccida with small, short-tubed white- or pale blue-flushed flowers, sofl-textured leaves and corms with basal cormlets from the Olifants River Valley and nearby; and I. sobolifera from the Western and Little Karoo, which has linear leaves, nodding spikes and flowers and corms with stolons. We divide I. sobolifera into three subspecies: subsp. carnea with pink flowers, is restricted to the Bokkeveld Plateau and nearby; subsp sobolifera with slate-blue flowers occurs in the Klein Roggeveld and nearby; and subsp albiflora with strongly scented white flowers occurs in the central Little Karoo. The taxon called I. rapunculoides var. namaquana (L.Bolus) G.J.Lewis, defined by a longer perianth tube, mostly 13-16 mm long, horizontally oriented, white, pale lilac or pink flowers and few-flowered lateral branchlets. is treated as I. namaquana, first described by H.M.L. Bolus in 1931. Plants referred to this taxon from south of its range at Hex River pass and nearby, however, have fully included anthers, a longer perianth tube. 16-20 mm. and ascending purple-pink flowers with a white cup and are referred to the new I. oxalidiflora. Two more varieties, I. rapunculoides var. subpendula G.J.Lewis and var. rigida sensu G.J.Lewis, which have upright flowers and distinctively branched stems are treated here as I. divaricata and I. contorta. Plants in the past included in var. rapunculoides from the Klein Roggeveld, south of the range of typical I. rapunculoides, have a longer perianth tube. 10-14 mm long, and attenuate, slightly lacerate. 5-veined. dry. rust-tipped bracts and comprise the new I. lacerata In addition, plants from streambeds in the Roggeveld that have large, white flowers, are not included in current accounts of the genus, and also represent a novel taxon, I. rivulicola. Lastly, I. rapunculoides var. robusta G.J.Lewis, the range of which falls entirely within that of var. rapunculoides and is usually sympatric with it. has pink flowers of similar structure, but four or five leaves and deep-seated corms with a collar of coarse fibres around the stem base. We raise this plant to species rank as I. robusta
New species of <i>Geissorhiza</i> (Iridaceae: Crocoideae) from the southern African winter rainfall zone, range extensions, taxonomic changes, and notes on pollen morphology and floral ecology
Authors: Goldblatt P. , Manning J. C. , Nänni I. 
Published: July 2015

Field work during the past 15 years has resulted in the discovery of 12 new species of the western southern African genus Geissorhiza Ker Gawl. and range extensions for several more. Following a survey of pollen morphology in the genus, we describe new pollen types in one section each of the two subgenera: five species of section Ciliatae Goldblatt and two of section Weihea Eckl. ex Baker have more complex apertures than the plesiomorphic single aperture with a 2-banded oper­culum found in other species. In addition, populations currently referred to the typical white (cream)-flowered G. inflexa (D.Delaroche) Goldblatt with larger, pink, red or purple flowers, have a third pollen type and are recognized as G. erosa (Salisb.) R.C.Foster. The new species are G. altimontana from the high Langeberg near Grootvadersbos; G. helmei from the Piketberg; G. lupidosa from the Du Toits Kloof Mtns; G. monticola from the Swartberg; G. platystigma from Darling, north of Cape Town; G. sufflava from the Piketberg; G. tricolor from Riversdale (all subgenus Weihea (Eckl. ex Baker) Goldblatt); and G. cantharophila from the Klein Roggeveld; G. demissa from the Kamiesberg. Gitberg and Cold Bokkeveld; G. exilis from the Waaihoek Mtns in the Worcester District; G. reclinata from the Swartberg: and G. saxicola from the northern Cedarberg-Pakhuis Mountain complex (all subgenus Geissorhiza). We also report range extensions and provide morphological notes for several species, including G. monanthos Eckl.. new collections o f w hich show that the inclusion of G. leuisiae R.C.Foster in that species was incorrect and we resurrect the species. The addition of 12 new species and recognition of G. erosa and G. lewisiae bring to 99 the number of species in the genus. New identification keys for Geissorhiza are provided that include all new species. We have also accumulated observations of floral ecology in the genus and integrate them with what is known about this aspect of the biology of Geissorhiza. Unusual strategies include deceptive pollination in G. tulhagh- ensis F.Bolus by tabanid flies and in two species, pollination using empid flies in combination w ith halictid bees
Taxonomy of the genus <i>Keetia</i> (Rubiaceae-subfam. Ixoroideae-tribe Vanguerieae) in southern Africa, with notes on bacterial symbiosis as well as the structure of colleters and the ‘stylar head’ complex
Authors: Tilney P. M. , Van Wyk A. E. 
Published: July 2015

The genus Keetia E.Phillips has a single representative in the Flora of southern Africa region (FSA). namely K. gueinzii (Sond.) Bridson. The genus and this species are discussed, the distribution mapped and traditional uses indicated. The structures of the calycine colleters, and the ‘stylar head' complex which is involved in secondary pollen presentation, are elucidated and compared w ith existing descriptions. Intercellular, non-nodulating, slime-producing bacteria are reported in leaves of a Keetia for the first time. Differences between the southern African representativ es o f Keetia, Psydrax Gaertn. Afrocanthium (Bridson) Lantz B.Bremer, and Canthium s. str.. which for many years were included in Canthium s.I., are given.
New synonyms and a new name in Asteraceae: Senecioneae from the southern African winter rainfall region
Authors: Manning J. C. , Goldblatt P. 
Published: July 2015

A review of the genera Othonna and Senecio undertaken for the forthcoming Greater Cape plants 2: Namaqualand-southern Namib and western Karoo (Manning in prep.) led to a re-examination of the taxonomic status of several species. This was facilitated by the recent availability of high-resolution digital images on the Aluka website (www.aluka.org) of the Drege isotypes in the Paris Herbarium that formed the basis of many species described by De Candolle in his Prodromus systematis naturalis regni vegetabilis. These images made it possible to identify several names whose application had remained uncertain until now. Each case is briefly discussed, with citation of additional relevant herbarium specimens. The following species are reduced to synonomy: O. incisa Harv. is included in O. rosea Harv.; O. spektakelensis Compton and O. zeyheri Sond. ex Harv. are included in O. retrorsa DC.; S. maydae Merxm. is included in S. albopunctatus Bolus, which is now considered to include forms with radiate and discoid capitula; S. cakilefolius DC. is included in O. arenarius Thunb.; S. pearsonii Hutch, is included in O. aspertdus DC.; S. parvifolius DC. is included in S. carroensis DC.; S. eriobasis DC. is included in S. erosus L.f.; and S. lobelioides DC. is included in S. flavus (Decne.) Sch.Bip. The name S. panduratus (Thunb.) Less, is identified as a synonym of S. erosus L.f. and plants that are currently know n under this name should be called S. robertiifolius DC. The confusion in the application o f the names O. perfoliata (L.f.) Jacq. and O. filicaulis Jacq. is examined. O. perfoliata is lecto- typified against a specimen in the Linnaean Herbarium (LINN) w ith radiate capitula. The name O. filicaulis correctly applies to a radiate species and is treated as a synonym of O. perfoliata. The vegetatively similar taxon with disciform capitula that is currently known as O. filicaulis should be known as () undulosa (DC.) J.C.Manning Goldblatt, comb. nov. The new name O. daucifolia J.C.Manning Goldblatt is provided to replace the later homonym O. abrotanifolia (Harv.) Druce.
The Cytology of Mycosphaerella pinodes*
Authors: Van Warmelo K. T. 
Published: July 2015

The behaviour of nuclei during ascus and spore formation and maturation in Mycosphaerella pinodes (Berk. Blox.) Stone was studied by means of the HCl-Giemsa technique. The mechanisms of dikaryotization could not be determined but typical croziers were formed. Nuclear fusion occurred in the young ascus and was followed by four conventional successive divisions. At pachytene the chromosomes could be counted and measured. The haploid chromosome number was found to be 15. Ascospore delimitation could be seen at metaphase IV so that each spore is homokaryotic. Two nuclear divisions occurred in the ascospores so that each cell became quadrinucleate.
Stochastic Collocation on Unstructured Multivariate Meshes
Authors: Narayan Akil , Zhou Tao 
Published: July 2015

AbstractCollocation has become a standard tool for approximation of parameterized systems in the uncertainty quantification (UQ) community. Techniques for least-squares regularization, compressive sampling recovery, and interpolatory reconstruction are becoming standard tools used in a variety of applications. Selection of a collocation mesh is frequently a challenge, but methods that construct geometricallyunstructuredcollocation meshes have shown great potential due to attractive theoretical properties and direct, simple generation and implementation. We investigate properties of these meshes, presenting stability and accuracy results that can be used as guides for generating stochastic collocation grids in multiple dimensions.
GPU Accelerated Discontinuous Galerkin Methods for Shallow Water Equations
Authors: Gandham Rajesh , Medina David , Warburton Timothy 
Published: July 2015

AbstractWe discuss the development, verification, and performance of a GPU accelerated discontinuous Galerkin method for the solutions of two dimensional nonlinear shallow water equations. The shallow water equations are hyperbolic partial differential equations and are widely used in the simulation of tsunami wave propagations. Our algorithms are tailored to take advantage of the single instruction multiple data (SIMD) architecture of graphic processing units. The time integration is accelerated by local time stepping based on a multi-rate Adams-Bashforthscheme. A total variational bounded limiter is adopted for nonlinear stability of the numerical scheme. This limiter is coupled with a mass and momentum conserving positivity preserving limiter for the special treatment of a dry or partially wet element in the triangulation. Accuracy, robustness and performance are demonstrated with the aid of test cases. Furthermore, we developed a unified multi-threading model OCCA. The kernels expressed in OCCA model can be cross-compiled with multi-threading models OpenCL, CUDA, and OpenMP. We compare the performance of the OCCA kernels when cross-compiled with these models.
Numerical Simulation for Moving Contact Line with Continuous Finite Element Schemes
Authors: Jiang Yongyue , Lin Ping , Guo Zhenlin , Dong Shuangling 
Published: July 2015

AbstractIn this paper, we compute a phase field (diffuse interface) model of Cahn-Hilliard type for moving contact line problems governing the motion of isothermal multiphase incompressible fluids. The generalized Navier boundary condition proposed by Qian et al. [1] is adopted here. We discretize model equations using a continuous finite element method in space and a modified midpoint scheme in time. We apply a penalty formulation to the continuity equation which may increase the stability in the pressure variable. Two kinds of immiscible fluids in a pipe and droplet displacement with a moving contact line under the effect of pressure driven shear flow are studied using a relatively coarse grid. We also derive the discrete energy law for the droplet displacement case, which is slightly different due to the boundary conditions. The accuracy and stability of the scheme are validated by examples, results and estimate order.
Error Estimates of Some Numerical Atomic Orbitals in Molecular Simulations
Authors: Chen Huajie , Schneider Reinhold 
Published: July 2015

AbstractNumerical atomic orbitals have been successfully used in molecular simulations as a basis set, which provides a nature, physical description of the electronic states and is suitable for 𝒪(N) calculations based on the strictly localized property. This paper presents a numerical analysis for some simplified atomic orbitals, with polynomial-type and confined Hydrogen-like radial basis functions respectively. We give some a priori error estimates to understand why numerical atomic orbitals are computationally efficient in electronic structure calculations.
Discrete Maximum Principle for the Weak Galerkin Method for Anisotropic Diffusion Problems
Authors: Huang Weizhang , Wang Yanqiu 
Published: July 2015

AbstractA weak Galerkin discretization of the boundary value problem of a general anisotropic diffusion problem is studied for preservation of the maximum principle. It is shown that the direct application of the M-matrix theory to the stiffness matrix of the weak Galerkin discretization leads to a strong mesh condition requiring all of the mesh dihedral angles to be strictly acute (a constant-order away from 90 degrees). To avoid this difficulty, a reduced system is considered and shown to satisfy the discrete maximum principle under weaker mesh conditions. The discrete maximum principle is then established for the full weak Galerkin approximation using the relations between the degrees of freedom located on elements and edges. Sufficient mesh conditions for both piecewise constant and general anisotropic diffusion matrices are obtained. These conditions provide a guideline for practical mesh generation for preservation of the maximum principle. Numerical examples are presented.