bluuebunny/crossref_metadata_2025 huggingface dataset:
SIEVE‐TUBE PLASTIDS OF HAMAMELIDIDAE ELECTRON MICROSCOPIC INVESTIGATIONS WITH SPECIAL REFERENCE TO URTICALES
Authors: Behnke H.‐D.
Published: April 2006

Ultrastructural analysis of sieve tubes of Hamamelididae (48 species from 16 families and 12 of the 15 orders investigated) showed a rather uniform distribution of S‐type plastids (storing starch only) among this subclass. P‐type plastids (storing protein) were reported only for the genus Ulmus. Some other species belonging to the Urticales contain sieve‐tube plastids storing neither starch nor protein; however, the scarce formation of minute starch grains in at least two species of the latter group joins them to the S‐type plastids.
PATTERNS OF SPECIES DIVERSITY AND THEIR EXPLANATION
Authors: Buzas Martin A.
Published: April 2006

Patterns of species diversity and equitability, and the hypotheses suggested to explain them are examined in the terrestrial and marine environments, and the fossil record. Although all the hypotheses are important in explaining diversity, none of them singularly or in various combinations are sufficient to explain the observed patterns. Quantification of the variables suggested to explain the observations will no doubt help clarify and give more credibility to the explanation of diversity, but such studies are only in their infancy.
GEOCARPON: AIZOACEAE OR CARYOPHYLLACEAE?
Authors: Bogle A. L. , Swain T. , Thomas R. D. , Kohn E. D.
Published: April 2006

Morphological, taxonomic, and field observations on the ecology of the monotypic narrowly endemic genus Geocarpon in southeastern Arkansas are presented, and the presence of anthocyanin pigments is demonstrated in plants of Geocarpon minimum, providing further support for its placement in the Caryophyllaceae rather than in the Aizoaceae to which it was originally assigned.
TYPIFICATION OF THE FERN‐GENUS CHRISTELLA LÉVEILLÉ
Authors: Holttum R. E.
Published: April 2006

The generic name Christella Léveillé is typified by the species Pohypodium parasiticum Linn. Thus typified the name can be used for a natural group of species which the author believes should have generic rank and of which he proposes to publish a monograph at a later date.
OPPORTUNITIES IN BOTANICAL HISTORY
Authors: Ewan Joseph
Published: April 2006

Four opportunities in botanical history obtain: pressing the search for records, saving historically valuable materials before they are lost, compiling informational retrieval aids, and writing interpretive biographies and social histories. Details of these opportunities are discussed with comments on the state of our knowledge and the location of materials.
DIOECIOUS SOLANUMS
Authors: Symon D. E.
Published: April 2006

A brief account is given of six dioecious species of Solanum all from north western Australia.
BIOSYSTEMATIC PATHWAYS ANNO 1969
Authors: Stafleu Frans A.
Published: April 2006

A review of some of the most recent developments in systematic biology. The present abundance of symposia in the field reflects the systematists' attempt to master an explosive development of knowledge in which many techniques and methods are used which formerly found little, if any, application in comparative biology. The information challenge is discussed with reference to modern processing methods and to abstracting. A shift in systematics from direct and visual characters to indirect, non‐visual data is apparent in many fields. The relation between numbers of known and possibly unknown taxa is illustrated by means of examples from the recent literature showing the rate of growth of our knowledge in various groups. The contributions by ultrastructural research, chemosystematics and molecular systematics are projected towards the future; other modern approaches in systematics (from ethology, ecology, micropaleontology, caryology, genecology) are mentioned briefly. The term biosystematics is used for evolutionary systematics of all living beings in the widest sense.
THE HANDLING OF CHARACTER VARIATION IN NUMERICAL TAXONOMY
Authors: McNeill J.
Published: April 2006

The problem of representing within‐OTU character variability in numerical taxonomy is considered and the limitations inherent in the restriction to single values, for example means or more seriously exemplar individuals, are emphasised. Jardine and Sibson's distinction between the attributes of individuals and the characters of populations or taxa is considered a useful one in its emphasis on the different treatment required for the comparison of individuals as OTUs as against that of groups. Existing methods of handling character variation are outlined and their limitations discussed. A new method, the character‐state frequency procedure, which can readily be incorporated into existing programs, is described and its effects on the analysis of two sets of data are outlined.
CIRCUMSCRIBING THE CONCEPT OF THE GENUS
Authors: Legendre Pierre
Published: April 2006

The present paper suggests that, despite its conceptual weakness, the cladistic approach to the delimitation of genera contains a valuable logical formalism. This logic could be applied to the dendrogram of the informational (genetic) similarity between the taxa to be classified. Even if this leads to a departure from a purely phyletic model of classification — that cannot be always maintained in a classification because of the internal limitations of the concept of classification — this approach corresponds much better to what we want a classification to be. A logical justification is given to phenetic taxonomy, when properly done.
FIFTY YEARS OF INTERNATIONAL BIOLOGY
Authors: Stafleu Frans A.
Published: April 2006

A review of the development of the International Union of Biological Sciences (IUBS) since its establishment in 1919, preceded by some remarks on the origin of ‘biology’ as a discipline and on nineteenth century international cooperation in the natural sciences. After a rather slow start in the years before the second World War in which the activities were mainly centered upon the section of botany, IUBS developed fully after 1945 into a truly representative international forum for biology. The most pressing problems facing biology and IUBS in the early seventies — documentation and the environment — are briefly discussed with special reference to the change of attitude apparent in biology, as well as in biologists from ‘pure’ and ‘detached’ to a social and cultural ‘engagement‘.
CHEMOSYSTEMATICS: RECENT DEVELOPMENTS
Authors: Turner B. L.
Published: April 2006

Recent developments in chemosystematics are reviewed with the conclusion that micro‐molecular data (essentially monomeric compounds such as flavonoids, alkaloids, terpenoids, amino acids, etc.) will prove most useful in resolving taxonomic problems at the generic level and lower while macromolecular data (polymeric compounds such as RNA, DNA, proteins, etc.) will prove most useful in resolving phyletic problems at the generic level and higher. Examples are given in which the two kinds of data have contributed to the resolution of such problems. Particular emphasis is placed upon the use of gas liquid chromatography in micro‐molecular studies, especially at the populational level. It is also concluded that protein‐band data and isoenzyme studies, as determined electrophoretically, because of the difficulty in establishing homology in the former and because of exceptional polymorphism in the latter, will be useful primarily at the specific level or lower. Developments have lagged in the application of serology and DNA hybridization to evolutionary problems in higher plant systematics and it appears that the most fruitful approach for unraveling phylogenetic pro. blems at the familial level or higher is that of animo‐acid sequence studies of metabolically important enzymes such as cytochrome c.
PROPOSALS FOR TREATMENT OF FUNGUS FAMILY NAMES WITH VERNACULAR TERMINATIONS
Authors: Petersen Ronald H.
Published: April 2006

Family names with vernacular terminations are discussed, especially as they relate to fungi, and changes in Art. 18, Note 2 and Art. 19, Note 2 and two new notes are proposed.
COMPUTERS IN BIOLOGICAL SYSTEMATICS, A NEW UNIVERSITY COURSE
Authors: Furlow J. J. , Morse L. E. , Beaman J. H.
Published: April 2006

A new course covering major aspects of the use of computers in systematics was recently offered at Michigan State University. The course consisted of lectures delivered by 12 speakers, discussion sessions, and reports on student projects. Topics included computers and systematics, the Flora North America Program, specimen identification and key‐construction by computer, parallels between specimen identification and medical diagnosis, plant disease diagnosis by computer, information problems in paleontology, distribution mapping by computer, biometrics and statistical studies with computers, probabilistic approaches to specimen identification, computers as aids to teaching systematic biology, numerical taxonomy, the modeling of genetic and evolutionary systems, possible computerized nomenclatural aids, and biogeographical analysis with computers.
THE CYTOGEOGRAPHY OF THE LORANTHACEOUS MISTLETOES
Authors: Barlow B. A. , Wiens D.
Published: April 2006

Known chromosome numbers in the Loranthaceae are reviewed and 102 new records added. The basic number of the family is x = 12 and there has been progressive aneuploid reduction to x = 8. The early development of the family has been under temperate conditions in the Southern Hemisphere, where stocks with x = 12 and 11 became established in temperate South America and Australasia. Rapid aneuploid reduction continued after the establishment of strong continental isolation, establishing numbers of x = 9 and 8 in the Old and New Worlds respectively. Massive secondary radiation in the tropics has followed, involving the 12‐, 9‐ and 8‐paired stocks.

Increase in chromosome size occurred during the tropical radiation, perhaps compensating for loss of recombination potential due to aneuploid reduction. Polyploidy is a rare and recent phenomenon in the history of the family, being documented in only two Central American taxa. One of these may be an autoploid.
GENETIC AFFINITIES BETWEEN HAWAIIAN AND MARQUESAN BIDENS (ASTERACEAE)
Authors: Gillett George W.
Published: April 2006

Genetic affinities are reported between 6 Hawaiian taxa of Bidens and one species (B. ahnnei) indigenous to the Marquesas Islands. An argument is presented supporting the longdistance dispersal of Bidens from the New World to the Hawaiian Islands, and the later dispersal of this stock to the islands of Southeastern Polynesia.
ON “NUMERICAL CHEMOTAXONOMY”
Authors: Weimarck Gunnar
Published: April 2006

The use of chemical characteristics in plant taxonomy is briefly surveyed. Some types of numerical treatment of variation in chromatographically separated substances are discussed. The usefulness of such methods is shown to be more restricted than is often claimed. The use of certain index values to illustrate differences between taxa or affinities between them is criticized from a biological point of view. An alternative possibility of the use of variation in chromatographically obtained data is suggested. A modified analysis of variance makes it possible to study population structures and genetical systems within one taxon at a time. Variation arising from irregularities in chromatographical separation, chance, etc., can also be estimated by this method.
TAXONOMIC PLACEMENT OF THE TYPHALES WITHIN THE MONOCOTYLEDONS: PRELIMINARY SEROLOGICAL INVESTIGATION.
Authors: Lee David W. , Fairbrothers David E.
Published: April 2006

Three types of serological precipitin techniques were employed, using seed extracts from selected monocotyledonous species and antisera to Typha and Sparganium. The obtained protein data were evaluated for use in helping to determine the placement of the Typhales within the monocotyledons. Data indicated the following: (1) significantly high serological correspondence between Typha and Sparganium, supporting the placement of these two genera within the order Typhales; (2) low serological correspondence between the Typhales and Liliales (in addition to some anomalous activity), indicating possible distant evolutionary relationships between these two orders; and (3) little or no serological correspondence between the Typhales and most of the tested monocotyledons, reflecting an isolated position for the Typhales within the monocotyledons.
THE GENERIC NAME HORNEMANNIA AND ITS DIVERSE APPLICATIONS
Authors: Stearn William T.
Published: April 2006

The attempts by contemporaries of J. W. Hornemann (1770‐1841) to commemorate him in the generic name Hornemannia resulted, for taxonomic and nomenclatural reasons, only in the creation of synonyms. Hornemannia Willd. (1809) was based on two species, one now referred to Mazus Lour. (1790), the other to Lindernia All. (1766). It prohibits the use of Hornemannia Vahl (1810) for a West Indian genus of Ericaceae subfam. Vaccinioideae, now to be called Symphysia C. B. Presl (1827), and of Hornemannia Benth. (1846) for an East Asiatic genus of Scrophulariaceae, now called Ellisiophyllum Maxim. (1871). Symphysia apparently comprises only one species, S. racemosa (Vahl) Stearn, first described as Hornemannia racemosa Vahl, which, being a montane little‐known plant, has been named anew from almost every West Indian island it inhabits.
CHEMOSYSTEMATIC AND NUMERICAL STUDIES OF NATURAL POPULATIONS OF JUNIPERUS ASHEI BUCH. †
Authors: Adams R. P. , Turner B. L.
Published: April 2006

Juniperus ashei Buch. was analyzed throughout its Texas distribution for areas of population differentiation and possible hybridization with J. virginiana L. and J. pinchotii Sudw. utilizing both morphological and chemical (terpenoid) characters. The volatile terpenoids of the foliage were analyzed by gas chromatography. Numerical methods included: analysis of variance; SNK tests; contour mapping of individual characters; differential systematics; and numerical taxonomy. Some peripheral populations of J. ashei show divergence of both terpenoid and morphological characters. This divergence is not, apparently, due to hybridization with J. virginiana or J. pinchotii. No evidence of hybridization was detected between J. ashei and J. virginiana or J. pinchotii. Differential systematics and numerical taxonomy were found to be of considerable value in the analysis of infraspecific variation.
RIND AND LEAF OILS OF TRIPLOID INTERSPECIFIC CITRUS HYBRIDS AND THEIR DIPLOID AND TETRAPLOID PARENTS
Authors: Scora R. W. , Cameron J. W. , Berg J. A.
Published: April 2006

Rind and leaf oils of triploid Citrus hybrids from 5 crosses, and their diploid and tetraploid parents, were analysed by gas chromatography. Two‐thirds of the chromosome complement of each hybrid was evidently contributed by the 4n parent. Overall, a wide range of percentages of the oil components occurred among hybrids and parents. There were differences significant at 1% in 80 of 90 parent‐hybrid group comparisons. There was no regular, dominating effect of the 4n parents, and in many cases the influence of 4n and 2n parents seemed about equal. However, among hybrids involving 4n lemon there was often a tendency for leaf oil levels to follow those of that 4n parent. The general absence of such an effect in the rind oils, and in the leaf oils of the other crosses, parallels the implication of an earlier study in which autotetraploids of several Citrus species were usually similar to their parental diploids, in their percentages of rind oil components.

Where 2 or 3 sets of hybrids had a common parent, either 2n or 4n, there was also no constant effect of that parent, from set to set, as compared to other parents involved. Variation in the percentages of any specific oil component was great among the 6 sister triploids in many crosses. Individuals sometimes approached the level of one parent, and sometimes that of the other. Transgression of one or more hybrids beyond either parent frequently occurred, and was particularly prominent with decanal, linalool, and linalyl acetate. Percentages of components in the leaf were often different from those in the rind.

It is clear that these polyploid hybrids of rather closely related species show many inherited differences in oil components. These differences are principally quantitative and probably reflect genetic recombinations which have altered intermediate biochemical pathways.
ZUR NOMENKLATUR DER PALÄOZOISCHEN GATTUNG TRISTACHYA LILPOP 1937 (SPHENOPSIDA)
Authors: Conert Hans Joachim , Schaarschmidt Friedemann
Published: April 2006

The name Tristachya Lilpop 1937 for an Upper Paleozoic plant similar to Sphenophyllum is a younger homonym to Tristachya Nees von Esenbeck 1829, a living genus belonging to the Gramineae. The new name Lilpopia is proposed instead of the illegitimate name.
AN INDEX FOR COMPARING WEEDINESS IN PLANTS
Authors: Hart Robin
Published: April 2006

An index for comparing weediness in plants can be constructed from site information on herbarium specimen labels. The percent of the species collected from disturbed sites is a measure of weediness. Some examples are presented in Cerastium, Polygonum, and Aster.
FLORA OF THE GUAYANA HIGHLAND: ENDEMICITY OF THE GENERIC FLORA OF THE SUMMITS OF THE VENEZUELA TEPUIS
Authors: Steyermark Julian A.
Published: April 2006

The summit flora of the table mountains of Venezuela would appear to be represented by a relatively small endemic generic element with an intermixture of nonendemic generic elements, originating and immigrating centripetally at different times and from different dispersals or origins (West Gondwanaland‐American, Australasian/Malaysian‐American, Australasia‐Antarctica‐American), the whole modified by evolution and differentiation on newly available areas of the table mountains during their erosional history and derivation from lowland peripheral sources during Pleistocene and post‐Pleistocene times.
ALGUNAS TENDENCIAS EVOLUTIVAS EN BURSERA (BURSERACEAE)
Authors: Rzedowski J. , Kruse H.
Published: April 2006

Se ensaya una síntesis de los conocimientos actuales acerca de las plantas pertenecientes al género Bursera, que agrupa alrededor de un centenar de especies de érboles (o a veces arbustos) caducifolios, distribuidos mayormente en la region intertropical americana, concentréndose sobre todo en la vertiente pacífica de México.

Se pasa revista a sus rasgos morfológicos més sobresalientes así como a sus afinidades ecológicas. En esta discusión se destacan: a) el carécter exfoliante de la corteza de numerosas especies de Bursera, con miras a la interpretación del significado adaptativo de tal propiedad; b) los diferentes tipos de mesocarpio ariliforme que se presentan en el género y la probable función de este órgano en la dispersión de las especies; c) dos tipos de hojas cotiledonares que se encontraron al revisar 29 especies de Bursera del Estado de Guerrero con respecto a este carécter.

Sobre la base de lo anterior, se trata de interpretar las tendencias evolutivas en el género en cuanto a: 1.—hébito de la planta, 2.—características de la corteza, 3.—tipo de hoja, 4.—características del mesocarpio, 5.—afinidades ambientales.

Se toca asimismo el aspecto taxonómico y el problema de las relaciones de Bursera con Boswellia y Commiphora, géneros, al parecer, estrechamente emparentados. Se propone un esquema hipotético del curso de la filogenia, en el cual se contempla la posibilidad de considerar a Bursera como un conjunto difilético.

This contribution attempts a synthesis of the present knowledge of the plants belonging to the genus Bursera, a group of ca. 100 species of deciduous trees (or sometimes shrubs), mainly distributed in American tropics and largely concentrated in the Pacific slopes of Mexico.

The most outstanding morphological features of these plants are examined as well as their ecological affinities. In this discussion special emphasis is given to: a) the exfoliating bark of many species of Bursera, with the aim of interpreting its adaptive significance; b) different types of aril‐like mesocarp occuring in the genus and its probable role in the dispersal of the plants; c) two different types of cotyledonary leaves found as the result of an examination for this purpose of 29 species of Bursera in the Mexican state of Guerrero.

On the basis of this discussion an interpretation of the evolutionary trends in the genus is essayed, with reference to: 1.—habit of the plant, 2.—bark characters, 3.—leaf‐type, 4.—mesocarp characters, 5.—ecological affinities.

The taxonomic aspect is also approached as well as the relationships of Bursera with allied genera: Boswellia and Commiphora. A hypothetical scheme of the possible course of phylogeny is proposed, in which Bursera as a diphyletic assemblage is conjectured.
STOMATAL PATTERNS IN EMBRYOPHYTES: THEIR EVOLUTION, ONTOGENY AND INTERPRETATION
Authors: Payne Willard W.
Published: April 2006

The history of study and nomenclature of stomatal concepts has not yet led to full elucidation of cell pattern significance for higher plants. In this paper, a new ontogenetic system of classification is introduced that makes primary subdivision on the basis of the mode of division of the guard mother cell (GMC) with respect to the wall which cuts it from the meristemoid: diameristic, at right angles; parameristic, parallel to; and anomomeristic, without special orientation to the preceding wall. These are further subdivided on the basis of ontogeny and number of the surrounding cells. The biology of stomata is discussed as it relates to cell patterning, and fundamental ties are pointed out between stomatal configurations and epidermal ontogeny, especially with regard to whether development is rectate, proceeding in a wave from an intercalary or marginal meristem, or diffuse, proceeding with continued meristematic activity within the expanding tissue over a long period of time. The concept of perigenous stomata, those in which protodermal cells act directly as GMC's without prior division, is refuted. The primitive stoma of land plant sporophytes is interpreted to be the simplest type of diameristic, mesoperigenous stoma, in which a protodermal meristemoid divides transversely, cutting off a distal GMC which then divides longitudinally to produce the guard cells. This stoma is suggested as the progenitor type for the Angiospermae, and is the primitive type for at least the Monocotyledonae.
THE ORIGIN OF AMMANNIA × COCCINEA ROTTBOELL
Authors: Graham Shirley A.
Published: April 2006

The wide‐ranging, native North American species Ammannia × coccinea Rottboell (Lythraceae) is determined, on the basis of morphological and cytological evidence, to be an amphidiploid derivative (n=33) of A. auriculata Willdenow (n= 16) and A. robusta Heer & Regel (n = 17). The latter species has not been recognized in modern floras but its specific status is supported by a unique combination of floral and vegetative characters and distinctive chromosome number. Artificial backcrosses produced vigorous, but pollen‐sterile F1's confirming the suggested relationship of the species. Geographical distribution of the complex is presented.
THE STATUS OF TWO NEW ENGLAND “ENDEMIC” CARICES: CAREX ELACHYCARPA AND C. JOSSELYNII (CYPERACEAE)
Authors: Reznicek A. A. , Ball P. W.
Published: April 2006

Two similar species of the Stellulatae group of Carex, Carex elachycarpa and C. josselynii were considered to be endemic to the state of Maine in northern New England. Their collection history, nomenclature and unusual morphology are reviewed. Carex elachycarpa was formerly placed in the genus Kobresia due to its possession of a split perigynium. This placement is shown to be untenable on morphological grounds. Close examination showed that both these taxa are aberrant forms of other species. Carex elachycarpa was found to be more or less dioecious with long anthers and is referred to the synonymy of C. sterilis with which it shares these features. Carex josselynii was placed with the synonymy of C. echinata because of its long beak and narrow perigynia. The wider occurrence in Carex of abnormalities found in these taxa such as split perigynia is noted.
THE RELATION BETWEEN ISOZYMES AND PLOIDY LEVEL. ITS APPLICATION TO BIOGEOGRAPHICAL STUDIES OF MUSCARI ATLANTICUM (LILIACEAE)
Authors: Oliver J. L. , Rejón M. Ruiz
Published: April 2006

In this paper a correlation between polyploid level and esterase isozyme pattern in individuals from different Spanish populations of Muscari atlanticum has been established. We have taken advantage of this correlation to make a study of the distribution of the reported polyploid levels in 1,017 individuals from thirteen natural populations. The interest in and application of this method for bio geographical analysis are discussed.
NOMENCLATURAL NOTES ON SOME BLACK YEAST‐LIKE HYPHOMYCETES
Authors: de Hoog G. S.
Published: April 2006

The name of the cellar mould is discussed in the light of Article 59 of the Code. Proposals are made to replace the generic names Leptodontium and Phaeococcus by Leptodontidium and Phaeococcomyces, respectively.
CLADISTIC ANALYSIS OF COMPLEX NATURAL PRODUCTS: DEVELOPING TRANSFORMATION SERIES FROM SESQUITERPENE LACTONE DATA
Authors: Seaman Fred C. , Funk V. A.
Published: April 2006

In the Asteraceae, the two most taxonomically significant aspects of the sesquiterpene lactone chemistry are the patterns of skeletal and substitutional diversity. Sesquiterpene lactones can be subdivided into different classes based on their carbon skeletons. Superimposed on each skeleton is a set of substituents which collectively define a specific compound. Both skeletal classes and substitutional features display taxonomically useful patterns of distribution.

A cladistic technique is demonstrated for converting these chemical features into taxonomic characters. Each character is derived via a biosynthetically based evaluation of structural diversity and determination of structural homology. Each set of homologous skeletal and substitutional characters from a taxon is arranged in a biogenetic transformation series. Outgroup comparison is used to determine the polarity of each character transformation series. The distribution of the resulting novel (apomorphic) skeletal and substitutional characters within this taxon are then used to generate a cladogram depicting the chemical synapomorphies. The chemistries of the taxa, Tetragonotheca L. and Iva L. (Asteraceae: Heliantheae), provide the two examples for the four‐step cladistic analysis. The methods employed in this analysis of sesquiterpene lactone distribution may also be applicable to other classes of complex natural products.
DR SMITH'S ANEMIA, OR, THE PREVENTION OF LATER HOMONYMS
Authors: Mabberley D. J.
Published: April 2006

Examination of the supplementary portion (1818‐1819) of Rees's Cyclopaedia and the seed‐lists and catalogues of European botanic gardens has revealed some 120 unlisted binomials, several making currently accepted names later homonyms so that Anemia radicans Raddi must be known as A. blechnoides Sm.; A. blechnoides Brade becomes A. spicantoides Mabb.; Aphelandra deppeana Schlecht. & Cham. is A. scabra (Vahl) Sm., Alyssum arenarium Lois. is A. loiseleurii P. Fourn. and Salvia inconspicua Benth. is S. protracta Benth. There may have to be changes in Acacia, Canna, Justicia, Pholiurus and Senecio, while names in Acacia, Acaena, Artemisia, Blechum, Bonapartea, Cassia, Cleome, Coleus, Commelina, Crataegus, Euphorbia, Ipomoea, Lotus, Psoralea and Stevia remain obscure.
PHILOSOPHIE DES COMPTAGES DE CHROMOSOMES
Authors: Favarger C.
Published: April 2006

Après avoir passé en revue et illustré par des exemples les principales causes d'erreur dans les comptages de chromosomes, l'auteur donne quelques recommandations pratiques pour les éviter le plus possible. Il montre que chez des polyploïdes élevés, il est parfois extrêmement difficile (sinon impossible) de savoir si le nombre zygotique est constant ou non dans une population. Il pense que la variation intraspécifique par Polyploïdie ou dysploïdie précède assez souvent la variation interspécifique et il montre combien il faut être prudent dans l'établissement du nombre de base x d'un groupe donné.
PRÉCIS, THE NATIONAL HERBARIUM OF SOUTH AFRICA (PRE) COMPUTERIZED INFORMATION SYSTEM
Authors: Morris J. W. , Glen H. F.
Published: April 2006

Developments in EDP‐IR within herbaria are briefly reviewed and progress with implementation of a data banking system by the National Herbarium of the Botanical Research Institute, Pretoria (PRE) is outlined. The three linked bases of the bank (literature, taxonomic information and specimen bases) are described. The numbering systems used for genera, based on that of de Dalla Torre & Harms, as well as those for species and families are described. Procedures which were used for encoding the 500 000 extant Southern African herbarium specimens in PRE as well as methods being used for accessioning new collections are outlined. Both a prototype query system (in operation) and a production query system (nearing completion) are described. Progress to date is discussed and ways in which encoding errors were obviated are highlighted.
RE‐ESTABLISHMENT OF GENUS CATUNAREGAM WOLF (RUBIACEAE) — A CONTRIBUTION TOWARDS THE PLANTS DESCRIBED IN RHEEDE'S “HORTUS MALABARICUS”
Authors: Tirvengadum D. D.
Published: April 2006

The validly published generic name Catunaregam Wolf (1776) based upon Rheede's “Katou‐Naregam” has been overlooked or ignored until Ross (1966) called attention to it. Having priority and being congeneric with Xeromphis Raf. (1838), it is here re‐established for a group of rubiaceous plants hitherto ascribed to that latter genus. New combinations for two Asiatic and one African species are given. Extensive preliminary work on the tribe Gardenieae (Rubiaceae) suggests deferring disposition of four other species commonly included in Xeromphis until further study can be completed.
DISTRIBUTION OF CYANOGENESIS IN LOTUS (LEGUMINOSAE)
Authors: Band Louise , Heyn Chaia C. , Plitmann Uzi
Published: April 2006

Single specimens and population samples (about 1000 plants in total) from 12 species of Lotus collected throughout Israel have been tested for cyanogenic compounds by the sodium‐picrate test. Various distribution patterns were found: In 3 species all plants were cyanogenic; in another 3 all were acyanogenic: and in the remaining 6 species varying degrees of cyanogenic polymorphism could be observed. Polymorphism tends to occur more often between than within populations of a species. A geographical trend was found only in L. halophilus where the ratio of cyanogenic plants in populations decreased towards the more arid areas. Except for the possible reduction in cyanogenesis in systematic groups with x = 6, no uniform correlation with morphotaxonomic or ecogeographic characters were found. Different Lotus species do not have a uniform response to conditions described previously as selective for or against cyanogenesis in L. corniculatus or Trifolium repens. For that reason no general hypotheses explaining the polymorphism of cyanogenesis can be formed and it is proposed that all such theories should be tested only at the specific level and even then within a regional frame.
THE GRASS SUBFAMILY CENTOSTECOIDEAE
Authors: Soderstrom Thomas R.
Published: April 2006

The centostecoid grasses comprise several genera of worldwide distribution, considered variously as a group, series, or subfamily. At the latter rank, the Centostecoideae must be validated by Latin description, which is offered here.
A COMPARATIVE PHYTOCHEMICAL INVESTIGATION OF THE GENUS BUPLEURUM L. (UMBELLIFERAE)
Authors: Carbonnier J. , Cauwet‐Marc A. M.
Published: April 2006

In the course of a phytochemical investigation of 124 populations within Bupleurum L. and some related genera. 78 constituents were found. The distribution of these compounds, as compared with the phyletic scheme of the group, indicates that a reduction in the number of constituents and a concomitant increase in synthetic specialization paralleled evolutionary advance.
THE ORIGIN OF LAND PLANTS: A PALEOBOTANICAL PERSPECTIVE
Authors: Taylor Thomas N.
Published: April 2006

The discovery of numerous fossil plants in recent years, together with the application of new techniques directed at understanding the total biology of the organism, has resulted in the modification of some ideas pertaining to the origin of land plants. Several of these lines of evidence strongly suggest the presence of a diverse terrestrial flora significantly earlier than the Upper Silurian bench mark currently used for the first appearance of plants with vascular tissue.
THE CLASSIFICATION OF POACEAE SUBFAMILY POOIDEAE
Authors: Macfarlane T. D. , Watson L.
Published: April 2006

Following a review of previous classifications, a revised scheme is presented for the 155 genera of Pooideae, derived via numerical analyses of original and compiled morphological and anatomical data and consideration of additional evidence. The subfamily is divided into two newly described supertribes, Poanae and Triticanae. These are further subdivided into the following tribes, all fully described: Poeae, Seslerieae, Meliceae, Aveneae and Agrostideae (in Poanae) and Triticeae, Bromeae and Brachypodieae (in Triticanae). The Aveneae are more narrowly circumscribed than is usual. The data employed in the numerical analyses are available, on microfiche, as full English descriptions.
POLLEN FINE STRUCTURE AND RELATIONSHIPS OF ACHATOCARPUS TRIANA AND PHAULOTHAMNUS A. GRAY
Authors: Skvarla John J. , Nowicke Joan W.
Published: April 2006

A palynological study of Achatocarpus Triana and Phaulothamnus A. Gray utilizing structural data from transmission electron microscopy (TEM), reinforces their close relationship as suggested by scanning electron microscopy (SEM) and supports family status as Achatocarpaceae. Both genera are known to have the betalain pigments and protein‐type sieve tube plastid which characterize the order Centrospermae. Affinities within the Centrospermae remain uncertain.
A PHYLOGENETIC ANALYSIS OF EXTANT SEED PLANTS: THE NEED TO UTILIZE HOMOLOGOUS CHARACTERS
Authors: Young David A. , Richardson P. Mick
Published: April 2006

The characters used in a recent phylogenetic analysis of land plants to derive the “Gneticae” and flowering plants from a common ancestor are critically evaluated. In our opinion, these characters are not homologous in the two groups and cannot be used in such a fashion. A cladistic analysis of seed plants (or land plants) is a worthwhile endeavor, but requires careful consideration of the homologous nature of the characters that are utilized in such an analysis.
STRUCTURAL AND EVOLUTIONARY ASPECTS OF THE FLAGELLAR APPARATUS IN GREEN ALGAE AND LAND PLANTS
Authors: Melkonian Michael
Published: April 2006

Ultrastructural features of the flagellar apparatus in green algae and land plants seem to be of considerable phylogenetic significance. Based on functional considerations details of the flagellar apparatus can be used to construct tentative lines of evolution within the green algae. An “ancestral” asymmetric zooflagellate possibly gave rise to a green unicell after a primary endosymbiotic event involving a green prokaryote. During the transition from phagotrophic to phototrophic nutrition in most green algae (the Chlorophyceae and Ulvaphyceae sensu Stewart & Mattox and most Prasinophyceae sensu Christensen) the original asymmetric flagellar apparatus was transformed into a 180° rotational symmetric flagellar apparatus with 4 flagella and a flagellar root system of the X‐2‐X‐2‐type. Most significant in this transition was presumably the evolution of the phototactic apparatus and of an apical flagellar groove. In the Charophyceae sensu Stewart & Mattox (including those green algae related to the ancestry of the archegoniate land plants) the early transition towards a terrestrial life, lack of an eyespot apparatus and development of a special type of oogamy possibly led to the evolution of the unilateral flagellar root in these organisms. It is suggested that the evolution of the unilateral MLS‐root in the Charophyceae sensu Stewart & Mattox can be traced back to an “ancestral green flagellate” before the evolution of the typical X‐2‐X‐2 flagellar root system. A tentative evolutionary scheme of the green algae mainly based on motile cell structure and mitotic and cytokinetic mechanisms is presented.
THE CONCEPT OF OVERLAP FOR EVALUATING LINKAGE DISTANCE AS USED FOR CLUSTERING
Authors: Newman K. W.
Published: April 2006

A procedure has been described for evaluating linkage between objects which are represented by points in a multi‐dimensional space in terms of overlap between replicates. An illustration of the procedure demonstrated its usefulness for the recognition and analysis of innate group structure.
ARGUMENTS FOR A GLOBAL CONCEPTION OF THE GENUS VIGNA
Authors: Maréchal R.
Published: April 2006

It is proposed that the genus Vigna be maintained in the broad sense and not be split up into smaller genera corresponding to presently recognized subgenera.
ISOTYPES AND SYNTYPES IN A LINDHEIMER TEXAS COLLECTION AT THE NATIONAL HERBARIUM OF CANADA, OTTAWA
Authors: Gillett John M. , Shchepanek M. J.
Published: April 2006

A list of isotypes and syntypes contained in a Texas collection of Lindheimer plants preserved at the National Herbarium of Canada in Ottawa, is presented.
HYBRIDIZATION AND AGAMOSPERMY OF BIDENS IN NORTHWESTERN ONTARIO
Authors: Crowe David R. , Parker William H.
Published: April 2006

Four weedy taxa of Bidens are common in Thunder Bay: B. cernua, B. connata, B. frondosa and B. vulgata. Since B. connata is intermediate in gross morphology and ecological preference between B. cernua and B. frondosa, and since it is only found in areas where B. cernua and B. frondosa are sympatric, an investigation was undertaken to determine whether B. connata is of hybrid origin (B. cernua × B. frondosa). Representative specimens of the 4 taxa were scored for 23 morphological characters, and these data were analyzed by Principal Coordinates Analysis. Seed germination and pollen viability were determined to be high with no significant differences among the 4 taxa. Morphological and cytological data suggest that B. connata (2n = 48) is the result of either a cross between an unreduced gamete of B. cernua (2n = 24) with a normal gamete of B. frondosa (2n = 48), or a cross between a 2n = 24 of B. frondosa with a typical gamete of B. cernua. Since B. connata shows no decrease in seed viability and apparently produces pollen by mitosis only, Thunder Bay populations of B. connata evidently comprise an agamic complex.
METHODOLOGY OF TAXONOMY
Authors: de Hoog G. S.
Published: April 2006

Taxonomy consists of three fundamentally different parts: (1) Representation, which consists of nominal, reproducible statements; (2) Ordering, which is a logical, verifiable science; and (3) Nomenclature, which is largely guided by practical application. Some proposals are made for the improvement of the scientific character of taxonomy.
A CLASSIFICATION OF PLANTS INTO HIGHER TAXA BASED ON CYTOLOGICAL AND BIOCHEMICAL CRITERIA
Authors: Edwards Peter
Published: April 2006

A variety of schemes are employed currently for the classification of plants into higher taxa. The two most widely used schemes, the traditional kingdom Plantae with sub‐kingdoms Thallophyta and Embryophyta, and the Whittaker five‐kingdom system with plants in the kingdoms Monera, Protista, Fungi and Plantae, rely on nineteenth century morphological criteria for delimitation of taxa that result in polyphyletic assemblages of organisms. It is proposed that plants be assigned to seven kingdoms, subordinate to the superkingdoms Procaryota and Eucaryota which are based on the procaryotic and eucaryotic types of cellular organization. The distribution of accessory chlorophylls is used as a major taxonomic criterion for classifying photosynthetic organisms at the kingdom level. This results in a single kingdom, the Cyanochlorobionta for photosynthetic plants containing chlorophyll a only within the superkingdom Procaryota. Photosynthetic plants within the superkingdom Eucaryota have been divided into three groups, the kingdom Erythrobionta for organisms with no accessory chlorophyll or occasionally chlorophyll d (and lacking flagella), the kingdom Chlorobionta for organisms with accessory chlorophyll b, and the Ochrobionta for those organisms with accessory chlorophyll c. Vascular plants have been assigned to a single division, the Tracheophyta, since in addition to having a similar biochemistry (chlorophylls a and b, similar carotenoids, starch as a reserve food product) they possess also a basic morphological groundplan ‐ a vascular system containing xylem and phloem, and a life history consisting of an alternation of generations. The fungi have been assigned three kingdoms as opposed to most extant schemes of classification in which they are allocated to a single polyphyletic assemblage. The true fungi have been divided into kingdoms Fungi 1 and Fungi 2 since it is thought that they have evolved from the Chlorobionta and Ochrobionta, respectively; the myxomycetes have been placed in a third kingdom, the Myxobionta.
GEITONOGAMY IN ANIMAL POLLINATED TROPICAL ANGIOSPERMS
Authors: de Arroyo Mary T. Kalin
Published: April 2006

Recent reproductive biology studies reveal high levels of self‐incompatibility in species diverse tropical communities. Many tropical trees are animal pollinated, pollen transfer patterns closely following the energetics of foraging. The energy output (in the form of nectar, pollen and other food bodies) of a single massively flowering tropical tree is far in excess of the demands of a single pollinating individual. This being so, a large proportion of the pollen transfers in tropical trees are geitonogamous and genetically equivalent to self‐pollination. It is here argued that the tendency for high levels of geitonogamy, which presumably increase with decreasing population density or increasing species diversity has been the major factor in the spread and perhaps initial evolution of pre‐zygotic self‐incompatibility mechanisms in the angiosperms.
INFRAGENERIC CLASSIFICATION OF HELIANTHUS (COMPOSITAE)
Authors: Schilling Edward E. , Heiser Charles B.
Published: April 2006

A formal infrageneric classification for the genus Helianthus is presented. The classification was derived using phenetic, cladistic and biosystematic procedures. The 49 species of Helianthus are placed into four sections and seven series.
ON THE CLASSIFICATION OF CAESALPINIOIDEAE
Authors: Pettigrew C. J. , Watson L.
Published: April 2006

Computer analyses of data on 41 characters compiled for 158 genera of Caesalpinioideae gave equivocal results at lower hierarchical levels, but pointed to the existence of two major series (Caesalpinieae + Cassieae + Dimorphandreae + most Sclerobieae/Amherstieae + Detarieae + two Sclerobieae), for which diagnoses are provided. The results are more in line with updated versions of Bentham's classification than with Hutchinson's. They are consistent with data on seed amyloid and also with observations on leaf transfer cells.
SEROLOGICAL APPROACHES TO THE SYSTEMATICS OF THE RUBIACEAE AND RELATED FAMILIES
Authors: Lee Yoo Sung , Fairbrothers David E.
Published: April 2006

Serological techniques have been employed in a systematic investigation of selected taxa of the Rubiaceae and selected putative relatives. Mature seed proteins were compared by quantitative and qualitative serological methods. Presaturation techniques were combined with the Ouchterlony tests to obtain additional data. An antiserum was presaturated and used in double diffusion tests to react against selected cross antigens. The combination of presaturation tests with double diffusion provided valuable information about the distribution of determinant groups. Various taxa belonging to 14 genera of Rubiaceae were reacted with taxa of the Apocynaceae, Asclepiadaceae, Caprifoliaceae, Cornaceae, Dipsacaceae, Gentianaceae, Nyssaceae and Umbelliferae. Quantitative data emphasized the similarity of the Rubiaceae to the Cornaceae and Caprifoliaceae. Presaturation tests using Rubiaceae antiserum revealed that the immunoprecipitating systems obtained with Apocynaceae, Asclepiadaceae and Gentianaceae were very similar to those systems obtained with the Cornaceae. Presaturation tests made it possible to determine that one or two systems were common to the five above families, and this has been interpreted as evolutionary similarity. Asperula and Galium were found to be serologically similar to each other, while being the two most dissimilar genera when compared with all other Rubiaceae genera.
THE LINNAEAN TYPES OF MENTHA (LAMIACEAE)
Authors: Tucker Arthur O. , Harley Raymond M. , Fairbrothers David E.
Published: April 2006

The nomenclature of certain polymorphic temperate genera, notably Crataegus, Mentha, Rubus and Salix, has been rendered more difficult by assumptions of type specimens and the consequential publication of illegitimate names. In Mentha alone, disregarding Gandoger (whose names were declared illegitimate at the Eleventh International Botanical Congress), almost 2300 names have been published for essentially 20 species; possibly 50% of these are synonyms, the remaining legitimate infraspecific names. To bring some order in the chaos of Mentha nomenclature, we herein set forth a choice and discussion of the Linnaean types using Savage (1945), Stearn (1957), Heller (1959), and Stafleu (1978) as our guides.
NOMENCLATURAL NOTES ON DRYOPTERIS: 4
Authors: Fraser‐Jenkins C. R.
Published: April 2006

The following nomenclatural judgements upon disputed or doubtful names are made in compliance with the Code, and changes made as follows: 1. Dryopteris austriaca (Jacquin) Woynar, based on Nephrodium austriacum Jacquin, can only have applied to Pteridium aquilinum (L.) Kuhn from its description, though the type is missing. A lectotype proposed by Jermy of a Dryopteris species cannot be taken as type material and is rejected as such, as are two other candidates for type material. A neotype is therefore designated. The name D. dilatata (Hoffm.) A. Gray is to be used instead for the Dryopteris species. 2. The name D. carthusiana (Vill.) H. P. Fuchs is retained as definitely applying to the taxon it is at present widely used for, despite the apparent absence of a type. A neotype is designated. 3. Dryopteris paleaceae (Sw.) Hand.‐Mazz. is the corrected citation for D. paleacea (Don) Hand.‐Mazz. and replaces D. wallichiana (Spreng.) Hyl., as it appears that Don was taking the name Aspidium paleaceum from Swartz without directly acknowledging it, though he does cite Swartz indirectly; therefore, Aspidium paleaceum Swartz, which is the earliest name, can be legitimately transferred to Dryopteris. The species concerned is found throughout tropical regions of the world, there being no major differences between the typical South American and Himalayan populations.
ARTIFICIAL AND NATURAL HYBRIDIZATION AND INTROGRESSION IN RHINANTHUS (SCROPHULARIACEAE) IN RELATION TO BUMBLEBEE POLLINATION
Authors: Kwak Manja M.
Published: April 2006

Flowers of plants obtained after artificial crosses between Rhinanthus minor L. and R. serotinus (Schönh.) Oborny are compared with flowers in field samples of mixed populations. Hybridization and introgression in different degrees are found to occur in the field. Arguments are given that the occurrence of both is influenced by the behaviour of flower‐visiting bumblebees and their numbers. In the field seed set in open‐pollinated hybrid plants was reduced compared with that of the parents. Variance in seed production is related to hybrid index value in open‐pollinated plants and to stigma position in caged ones. Stigma position is an important character for the direction of hybridization and introgression.
DICHAENA RUGOSA FRIES AND ITS IMPERFECT STATES, PSILOSPORA FAGINEA (PERS.) RABENH. AND DICHAENOPSIS NOTARISII PAOLI
Authors: Speer Eberhard O.
Published: April 2006

Having considered the publications over the past 240 years devoted to the nomenclature and taxonomy of Dichaena, it has been found that the legitimate name for its ascus form is Dichaena rugosa. For the conidial states the valid names are Psilospora faginea and Dichaenopsis notarisii. Observations on the spermatia and receptive hyphae are mentioned.