bluuebunny/crossref_metadata_2025 huggingface dataset:
Conservación in situ y ex situ de las agaváceas y nolináceas mexicanas
Authors: Franco-Martínez Irma Sonia
Published: January 2019

The Agavaceae and Nolinaceae, as other plant families, have been affected by the destruction and modification of their habitats and by selective extraction with commercial purposes of some of their species. This has generated that 48 species of Agavaceae and Nolinaceae have been included in the list of Mexican plants in risk of extinction (NOM-059-ECOL-l 994), and two of them (Agave parviflora and Agave victoriae-reginae) are listed in the appendices of CITES. There are 30 Protected Natural Areas that conserve in situ at least one species of the Agavaceae or Nolinaceae. The ex situ conservation is done in 38 Botanical Gardens, 22 of them include in their collections at least one species of these families. There are also eight commercial nurseries that have started the propagation by seed of 12 species, mainly from the genus Agave. Case studies on Agave victoriae-reginae, Beaucarnea recurvata and Yucca schidigera, are also analyzed.
Riqueza de especies y endemismo del componente arbóreo de la Península de Yucatán, México
Authors: Ibarra-Manríquez Guillermo , Villaseñor José Luis , Durán-García Rafael
Published: January 2019

Based on exhaustive studies of herbarium specimens held at the National Herbarium of Mexico (MEXU), as well as of the literature, an updated list of the native species of trees of the Mexican portion of the Yucatan Peninsula is provided (Campeche, Quintana Roo y Yucatan). For each species the state(s) in which it occurs is cited. The list includes 437 species belonging to 246 genera and 68 families. An appendix listing 376 excluded species, including 68 of dubious occurrence in the peninsula is provided, clarifying the reason for their exclusion as members of the flora of the Peninsula. The richest families are Mimosaceae, Euphorbiaceae, Fabaceae, Rubiaceae, and Myrtaceae; the richest genera are Acacia, Eugenia, Coccoloba, Croton and Lonchocarpus. The percentage of endemism is around 12.3% (54 taxa in 26 families); the families with more endemic species are Cactaceae, Fabaceae, Mimosaceae, Polygonaceae and Rubiaceae. At the state level, Quintana Roo harbors the most species (351). The use of five different similarity coefficients (Braun-Blanquet, Dice, Drive & Kroeber, Jaccard and Simpson) to analyze both the total number of species and the endemic ones, supports the idea of considering the states as part of the same floristic province. Finally, the need to intensify the floristic and taxonomic work, aimed at evaluating in the near future more properly the floristic richness in the Peninsula is pointed out. This will allow a more precise definition of its floristic subdivisions, its degree of endemism and its floristic relationships with neighbouring regions.
Anatomía sistemática de la familia Anacardiaceae en México. l. La corteza secundaria de Tapirira Aublet.
Authors: Terrazas Teresa
Published: January 2019

Tapirira bark anatomy is described for the species distributed in Mexico. Results show that there are anatomical characters with diagnostic value that contribute to distinguish-between species. Bark ray dimensions (height and width) and diameter of the bark radial canals distinguish T. chimalapana from T. mexicana as do wood ray dimensions and wood radial canals. Ondulate periderm, esclerified phelloderm and yellow-brownish exudate characterize T. chimalapana, while T. mexicana possesses straight periderm, esclerified phellem and reddish exudate. Both species show a laminated rhytidome, more conspicuous in T. mexicana. Further studies in the species of T. guianensis group are essential to support the diagnostic value of the aforementioned characters.
Anatomía de la madera de ocho especies de angiospermas de clima templado
Authors: Quintanar Alejandra , Pérez-Olvera Carmen de la Paz , De la Cruz-Laina Isabel , Razo-Balcazar Daría
Published: January 2019

Wood anatomy of Alnus acuminata Kunth, Ostrya virginiana Rose, Quercus dyseophylla Benth. and Quercus glabrescens Benth., Arbutus glandulosa DC., Arbutus tessellata Sorensen, Styrax argenteus Presl. and Buddleia wrightii Robinson, collected in the state of Jalisco and Puebla are given. For each studied taxa, distinctive anatomical features are rebounded, and for each microscopic characteristic, photographs are given. Recommendations on their uses are suggested.
Métodos de análisis de datos en la germinación de semillas, un ejemplo: Manfreda brachystachya
Authors: González-Zertuche Lourdes , Orozco-Segovia Alma
Published: January 2019

Methods for germination analysis were reviewed in this work. These methods were divided in graphical and analytical (Indices and curve fitting to logistic and normal distribution functions). Each one was illustrated with the Manfreda brachystachya germination data in a temperature gradient. Germination parameters were underlined: capacity and rate germination, mean time, and variance in mean time germination. These parameters must be measured accurately. The advantages and disadvantages of the different methods are discussed. Indices which try to relate germination capacity with time are not recommended to obtain relative values of germination rate, because they confound the effects that can have the different parameters. The use of logistic and normal functions are recommended, because they are models that analyze germination behavior in time and provide the values of the main germination parameters.
Flora vascular de la Sierra Monte Grande, municipio de Charcas, San Luis Potosí, México
Authors: Reyes-Agüero J. Antonio , González-Medrano Francisco , García-Pérez José D.
Published: January 2019

Monte Grande mountain range is a small (41.8 km~) area located in the north San Luis Potosi high plateau. The characteristic vegetation include oakscrub, pinyon woodland and three types of xerophytic scrub. The flora of this area comprises 74 families, 242 genera and 397 species; 45 of these species represent new records for the San Luis Potosi high plateau.
Epistemología de la investigación taxonómica: inferencias filogenéticas y su evaluación
Authors: De Luna Efraín
Published: January 2019

A problem in systematics is how to decide which similarities are reliable inferences of genealogical history (homologies) . Und.er a cladistic approach, these inferences are subjected to critical examination that would potentially falsify them with the principle of parsimony. Among equally supported hypotheses, the most parsimonious hypothesis must be preferred if it explains most observations that require to be explained as satisfactorily as any other less parsimonious ex planation. Each inference of homology is questioned in view of congruence with other characters in the most parsimonious phylogenetic hypothesis. In such hypothesis, initial inferences about homology can be changed as inferences about homoplasy. In contrast, in the evolutionary approach, the criteria for the validation of homologies are conventional notions about the evolutionary, reproductive, adaptive, or functional importance of characters. Using these criteria, the validation of inferences is established a priori, therefore remaining immune to any further questioning. If taxonomic groups should be recognized by the common genealogical history of included elements, then inferences that could be tentatively accepted as valid hypothesis of phylogeny are those justified as the most parsimonious.
Adopción de árboles nativos valiosos para la restauración ecológica y la reforestación
Authors: Vázquez-Yanes Carlos , Batis Ana Irene
Published: January 2019

Based on the omnipresent destruction of most natural plant communities and on its consequences on the deterioration of the environment, the need for ecological restoration, re forestation and development of agrosilvopastoralist systems, composed by domesticated native woody plants is urged. The domestication of wild plants is based on the knowledge of their biological and ecological traits and about the best suited propagation mea ns, and the possible amelioration of the clones and lines by using clonal o sexual selection of the best plant traits or by means gen e tic engineering techniques. The importance of a national initiative for plant domestication is discussed.
La vegetación de México: Una visión histórica
Authors: Cevallos-Ferriz Sergio RS , Lozano-García Socorro
Published: January 2019

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Aspectos de la historia de la vegetación de México con base en macrofósiles de angiospermas
Authors: Cevallos-Ferriz Sergio R.S. , Silva-Pineda Alicia
Published: January 2019

The history of Mexican vegetation is mainly known through extrapolations based on its extant flora and/or paleobotanical work done in other countries. While macrofossils corroborate that in the past, as in the present, the Mexican flora had relationships with those of other areas, its study reveals that during the Cretaceous it had affinities with the boreal floras, though, some of the d escribed plants have close phylogenetic relationships with plants now growing naturally in the southern hemisphere. During the Tertiary the relationship with the boreal floras continued, suggesting that if some taxa originated in Gondwana, at least some of their genera and species could differentiate and radiate in the northern hemisphere, as suggested by some Anacardiaceae and perhaps other Leguminosae. A legume, Lysiloma, suggest that endemic taxa that characterize the extant Mexican vegetation have a long history, since they are known from Oligocene sediments. Another plant of the same family, Reinweberia, also suggest that during the Tertiary there were endemic plants that became extinct, and underscores the fact that for a long time the Mexican vegetation have had a distinct composition. The macrofossils of angiosperms suggest that only recently, perhaps no more than 10 million years ago, the vegetation types recognized today were established, although, those of the past could be similar.
Algunos aspectos de la evolución de la vegetación de México
Authors: González-Medrano Francisco
Published: January 2019

Various factors have influenced the characteristics of vegetation over Mexico such as: geographical position, orography, volcanism, emersions and immersions, climatic fluctuations during the Tertiary, glaciations as well as various migrations that have taken place at various times in various directions. Another aspect that has contributed to the diversity in flora and vegetation in Mexico is the development of an endemic element in flora and even in vegetation. This is important specially to xerophitic and temperate forest. All of this results in a complex phytogeographic analysis of flora due to the co-existence, in some communities, of plants with various origins, ages and evolutive histories.
Caracterización preliminar de una secuencia homóloga del gen LEAFY en gimnospermas (Pinus radiata Lemm.)
Authors: Izquierdo Liz Y. , Tapia Rosalinda , Vergara Francisco , Álvarez-Buylla Elena
Published: January 2019

A fragment from an homologous sequence of LEAFY (LFY) gene that encodes for a transcription factor involved in early events during inflorescence development was cloned from genomic DNA of P. radiata, a non flowering seed plant. Using PCR technic we amplified an 85 bp fragment flanked by two primers designed from some DNA sequences obtained from different species of angiosperms. The fragment obtained was.highly similar to A. thaliana gene LFY between 5077 and 5143 bases and hybridized with a LFY clone from this species. This result suggests that sorne molecular components of the functional and structural complexity of the development of reproductive structures in higher plants are an ancestral property of seed plants and not a novelty in the angiosperm lineage.
Tipos de vegetación y diversidad Beta en el Valle de Zapotitlán de las Salinas, Puebla, México
Authors: Osorio-Beristain Oscar , Valiente-Banuet Alfonso , Dávila Patricia , Medina Rosalinda
Published: January 2019

The Zapotitlán de las Salinas Valley located in the South Western portion of the Tehuacán-Cuicatlán Valley, harbors a high plant diversity with a high proportion of endemism. In this study we describe the different plant communities along an altitudinal gradient between 1350 to 1700 meters above the sea level, in the vicinities of the Cerro Cutá, emphasizing on the differential species distribution among communities (? diversity). The plant communities description was conducted considering the different geomorphic surfaces (slopes with different Iithologies, altitudes and aspects, alluvial deposits along the Salado River and flat zones on the top of hills) and they were described by means of field samplings analyzing their structure and composition . The vegetation-type diversity is associated to soil and lithological heterogeneity in the study site producing a mosaic of plant communities in which a total species turnover of 71.3% indicates a high number of species restricted to different vegetation types. This high ? diversity contributes to the high regional diversity (y-diversity) reported for the Zapotitlán Valley.
La problemática socioambiental e institucional de la reforestación en la Región de la Montaña, Guerrero, México
Authors: Cervantes Virginia , Arriaga Vicente , Carabias Julia
Published: January 2019

The authors analyze the causes that have prevented the successful operation of reforestation programs in the La Montaña region (Guerrero State), Mexico. They reviewed the various regional development programs which have taken place in the last six decades and which have included the implementation of reforestation programs as part of their activities. The authors conclude that the meagre success that has characterized the reforestation efforts at La Montaña is due to one or a combination of several of the following factors: l] reforestation objectives not directed towards the restoration of the environment, 2] programs based on a very small number of the species, 3] technical deficiencies in the selection of species and sites for the plantations 4) small size of areas devoted to reforestation, 5] insufficient and intermittent funding for these programs, 6) lack of training of local peasant inhabitants and of institutional technicians, and 7) very limited social acceptance of reforestation programs.
Géneros de Theaceae: aspectos taxonómicos y nomenclaturales
Authors: Luna Isolda , Villaseñor José Luis
Published: January 2019

The family Theaceae is distributed in the tropical and subtropical regions of the world. Its main center of richness and diversification is found in Asia where most of the genera are found, including the most plesiotypic as well as several more derived. As recognized in this work, the family is composed by 20 genera, all defined by sharing all the species at least one sinapomorphy. Recognizing of the genera was the result of an exhaustive revision of literature, the rigorous verification of numerous characters of taxonomic importance by studying herbarium specimens hold in several herbaria that include good material of this family, especially types. Based on a phylogenetic hypothesis described in an unpublished paper and the synthesis of the generic delimitations within Theaceae, the proper name for each genus and their synonyms is provided.
Sistemática filogenética: teoría, análisis y datos
Authors: González Dolores , De Luna Efraín
Published: January 2019

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Codificación de las inserciones-deleciones en el análisis filogenético de secuencias génicas
Authors: González Dolores
Published: January 2019

The general concept of phylogenetic homology visualizes that a character is any aspect of the phenotype or genotype that varies inside a group. In gene sequences each position corresponds to a hypothesis of transformational or taxic homology depending if the nucleotides vary or not in each position. It is theoretically difficult to designate a proper code to an indel. This is because an indel can be interpreted as an artifact or as phylogenetic information (taxic or transformational homology). A review of the distinct codes employed for the analysis of the indels shows that the six codes used are: ( 1) missing, (2) excluded, (3) fifth state, ( 4) presence/absence, (5) different length /several states and (6) different length /several characters. Each code was evaluated in the phylogenetic hypotheses of the phytopathogenic fungi Rhizoctonia solani with a matrix of 20 sequences of the ribosomal ARN genes. The effects of the distinct codes were measured in changes of homoplasy, topology, resolution and tree number. The effects differ depending on the code used. The most radical effect was caused by the coding of the indels as different length/several characters. The cladistic analyses with gene sequences should include an evaluation of the effects of the different codes for the indels, since they may be potentially informative.
El concepto de homología filogenética y la selección de caracteres taxonómicos
Authors: De Luna Efraín , Mishler Brenth D.
Published: January 2019

El problema práctico de seleccionar caracteres taxonómicos no solo requiere una amplia base empírica. También exige un examen de las teorías y los principios epistemológicos detrás del análisis del carácter. Esta revisión sostiene que la selección de caracteres equivale a elaborar y evaluar hipótesis de homología. Basado en un concepto filogenético de homología como continuidad histórica entre características o eventos en diferentes organismos, un carácter taxonómico se ve necesariamente como un sistema de al menos dos homólogos (estados de carácter). El principio de Hennig postula que los estados compartidos apomórficos (sinapomorfia) constituyen la única evidencia justificada para reconocer grupos taxonómicos. Los principios epistemológicos para el reconocimiento de homología (caracteres) incluyen argumentos empíricos y lógicos. Las bases empíricas son semejanza, conjunción y variación discreta, heredable e independiente. Un argumento lógico para la evaluación de la homología es la búsqueda de la congruencia de caracteres mediante el principio de parsimonia inferencial. Este trasfondo teórico revela que las hipótesis de homología son el resultado de un proceso de inferencia, por lo tanto, los enunciados de homología dependen lógicamente de un conjunto de datos específico y un cladograma particular. El concepto filogenético de homología y los principios epistemológicos revisados ​​aquí se aplican a todos los sistemas de caracteres, incluidos los de biomoléculas como el ADN. Los procedimientos y la tecnología para obtener cada tipo de carácter variarán, pero la ontología básica para su análisis es la misma.
Psilotum complanatum Sw. en el Pedregal de San Ángel
Authors: Galindo-Rosete Carlos , López-Toledo Leonel
Published: January 2019

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Plantas leñosas raras del bosque mesófilo de montaña II. Ticodendron incognitum Gómez-Laurito & Gómez P. (Ticodendraceae)
Authors: Meave Jorge , Gallardo Claudia , Rincón Armando
Published: January 2019

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Editorial
Authors: Oyama Ken , Magaña Patricia
Published: January 2019

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Germinación de Chiranthodendron pentadactylon Larr. (Sterculiaceae), en respuesta a la escarificación, temperatura y luz
Authors: Osuna-Fernández Reyna , Laguna-Hernández Guillermo , Brechú-Franco Alicia , Orozco-Segovia Alma
Published: January 2019

Seed quality and seed germination with scarification and non scarification and variable temperature and light were determined in Ch. pentadactylon seeds form two places of Guerrero and Oaxaca. Also seed viability was determined in seeds from Guerrero stored 6 months at 5º C. Seeds showed to be orthodox and dormant due to an impervious seed coat. The seeds from Guerrero had higher weight, length and water content than those from Oaxaca, however the scarified seeds from Oaxaca reached a higher germination percentages. Germination of scarified seeds of the two populations was enhanced by alternated temperatures and inhibited by far red light. Germination under darkness, red light and white light did not differ significantly. In soil some seeds could be dormant under a low ratio red:far red light transmitted by litter. The differences between the two populations might be due to a maternal effect induced by weather conditions in their geographic localities.
Diagnóstico del conocimiento etnobotánico actual de las plantas medicinales de la Península de Yucatán
Authors: Méndez Martha , Durán Rafael
Published: January 2019

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Estructura y composición florística del Cerrado en el Parque Nacional Noel Kempff Mercado, Santa Cruz, Bolivia
Authors: Mostacedo-C. Bonifacio , Killeen Thimoty J.
Published: January 2019

We studied the structure and floristic composition of the Cerrado vegetation in two sites at the Parque Nacional "Noel Kempff Mercado", Santa Cruz, Bolivia. The results indicated that the sites are located within two different types of Cerrado communities: 1) cerrado and, 2) cerradao. The lower stratum (50 cm) was dominated by grasses, while higher strata were dominated by shrubs and sub-shrubs in the cerrado, and by trees in the cerradao. We founded 41 families, 90 genera, and 112 species in the cerrado, and 37 families, 39 genera and 106 species in the cerradao. For both sites, the plant families with greater coverage and species richness were: Gramineae (29 species, 51 % cover), Leguminosae (23 species, 4.8-5. 7% cover) and Guttiferae (3 species, 1-20% cover). Other important families were: Myrtaceae, Rubiaceae, Euphorbiaceae and Melastomataceae, with 7,6 species; 4,6 species; 8, 2 species; 2, 6 species for cerrado and cerradao, respectively. Herbs are the most important for the number of species, followed by grasses and shrubs in the cerrado and by shrubs, followed by herbs and grasses in the cerradao. Floristic similarity between the two communities was relatively low (39% according to Sorensen index).
Sistemática filogenética y el concepto de especie
Authors: Mishler Brent D. , De Luna Efraín
Published: January 2019

There actually is no species problem per se in systematics. Rather, there is a taxon problem. This review argues that a decision must first be made about what entities taxon names are to represent in general. Then, species taxa should be the same kind of things, but just the least inclusive taxa that are named using the formal Linnaean nomenclatorial system. Formal classifications are meant to serve purposes of communication, data storage, predictivity, and function in theories. These purposes are best served by naming only phylogenetically natural, monophyletic groups. These are groups containing all and only descendants of a common ancestor. A phylogenetic species concept can thus be defined, based on a generalized view of the meaning of monophyly and synapomorphy. In the process of building a classification , taxonomic groups are recognized on the basis of clear support for their existence as monophyletic cross-sections of a lineage. Also, formal taxa are named considering their utility in developing and discussing evolutionary process theories.
Biología de las plantas carnívoras: aspectos ecológicos y evolutivos
Authors: Alcalá Raúl E. , Domínguez César A.
Published: January 2019

Carnivorous plants have the ability for attracting, catching, digesting and assimilating preys, through morphological and physiological specializations of theirs leaves. In this work we review some poorly studied aspects regarding the ecology of carnivorous plants, as well as, the selective pressures that have shaped the characteristic attributes of these plants. In particular, we emphasize those aspects related with the mechanisms of prey attraction, the selective value of capture, the existence of a trade-off between capture and pollination evolution, and the role of selective constraints on the evolution of the carnivorous habit.
El uso de marcadores moleculares en las ciencias vegetales
Authors: Oyama Ken
Published: January 2019

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Isoenzimas
Authors: Pérez-Nasser Nidia , Piñero Daniel
Published: January 2019

This work presents a review of the use of enzymes as molecular markers for evolutionary studies, in particular population genetics. First, the methodology of starch electrophoresis is shown as a useful tool To detect variation within and among populations. Second, applications to evolutionary biology are presented. In plants these markers have been used for 1] to study mating systems, 2] do phylogenetics and taxonomy, 3] study natural selection components, 4] to correlate genetics and life history characters and 5] understand the origin and evolution of cultivated plants and their wild relatives
El uso de los RAPDs como marcadores moleculares en plantas
Authors: Otero-Arnaiz Adriana , De la Cruz Marlene , Oyama Ken
Published: January 2019

In this paper a review of RAPDs (Random Amplified Polymorphic DNA) as molecular markers is presented. This molecular marker has been used to genetic mapping, population genetic structure, genetic identification, intra and interspecific variation, reconstructing phylogenies and conservation biology. In general, RAPDs have been useful to estimate genetic diversity, genetic identification of taxa, clones, varieties and hybrids. However, their use in Systematic has been questioned due to the difficulties in the determination of identity, homologies and independence of characters. Methods of analyses used to estimate genetic diversity are briefly described. Finally, some recent advances and new technics based on PCR are presented.
Sistemática molecular: comparación entre diferentes métodos y sus aplicaciones
Authors: Martínez Mahinda
Published: January 2019

The use of molec ular techniques to solve sys tema tic problems has become very popular in recent years. One technique used in botany is DNA/DNA hybridization , in which single strands of DNA from closely related genera or species are reassociated , but requires that differences in sequences between taxa are lower than 20%. Iso and allozyme electrophoresis is another technique which has the advantage of a wider range of applications, such as the divergence of infraespecific taxa, species delimitation , phylogenetic reconstruction , hybrid speciation, and detection of polyploidy. Restriction enzymes are used to cut ribosomal DNA to detect differences at the species level, for species complexes and among genera. These enzymes are also used to cut chloroplast DNA to determine the ancestry of cultivated plants, as well as, to de limit subgeneric, tribal, subfamilial, order, subclass or class classifications. Nucleotide sequences have been used in nuclear or chloroplast genes utilizing slow evolving genes for separation at the family or subfamily levels and fast evolving genes for delimiting genera, subgenera or sections.
El análisis filogenético: métodos, problemas y perspectivas
Authors: Eguiarte Luis E. , Souza Valeria , Nuñez-Farfán Juan
Published: January 2019

In the last century, Darwin and Haeckel were the first to propose the phylogenetic trees. The first phylogenies were made intuitively, but in the fifties several researchers tried to propose rules for their reconstruction. The evolutionary school in tended to use the principies of evolution, the numerical (or pheneticist) school advanced the "distance methods", while the cladistic school proposed the "parsimony method". The UPGMA and the Neighbor:Joining are the more commonly used distance methods. The parsimony method tries to find the tree that requires the smallest number of changes. There are other methods that take in to account the evolutionary forces, like the maximum likelihood (Felsenstein, 1981). In this paper we discuss some of the problems associated to phylogeny reconstruction, the advantages of the different methods and of some of the computer available programs, and finally we offer a perspective on the uses of the phylogenies.
Ontogenia de la semilla de Yucca periculosa (Agavaceae)
Authors: García-Villanueva Eduardo , Engleman E. Mark
Published: January 2019

Seeds of several Yucca species have been studied by Arnott and Horner. They mainly studied the nature condition and stated that the extra-embryonic food reserve tissue is a perisperm. This paper provides ontogenic evidence that this tissue is an endosperm with nuclear development type. The seed shape is nearly a triangular prism less than 1 cm long, black color and the raphe groove is conspicuous. The seed coat is derived exclusively from the outer integument. The exotesta external periclinal cell wall appears with irregular thickness. Both mesotesta and endotesta grow irregularly inward the seed confering to the endosperm a ruminate appearance. Toward seed maturity, the inner integument tissues disappear, thus fusion between intertegumentary and tegmen-nucellar cuticles occurs; valuable ontogenic information is showed by the cuticles, due to its persistence in spite of its generative tissue disappearance. The embryo development increases until 10 weeks after anthesis, it is cylindric, folds like "S" and two thirds of its chalazal lenght correspond to the cotyledon.
Influencia de los mezquites en la composición y cobertura de la vegetación herbácea de un agostadero semiárido del norte de Guanajuato
Authors: Cruz-Rodríguez Juan Antonio , García-Moya Edmundo , Frías-Hernández Juan Tenorio , Montesinos-Silva Genaro , Flores-Flores José Luis
Published: January 2019

It has been said for a long time that mesquite reduces significantly cover and productivity of herbaceous vegetation in the range lands. Likewise there are evidences showing the opposite. This controversy make us think that this interaction is not fully understood. This work evaluated the effect of mesquite on the herbaceous vegetation along a gradient which range from open to a heavy dense stands. It was found that isolated arboreal mesquites reduced up to 50% the photosyntetic photon flux density which are not limiting for C4, species, whereas clustered shrubby mesquites reduces 75 % which can limit the growth of these species. Such conditions creates three plant groupings: the first made up of short and caespitose grasses which grow in the open. The second with a better and more diverse group growing under the tree canopy, dominated by bunchgrasses, cacti and shrubs. The third under the close canopy of the clustered shrubby mesquites with shrub dominance.
Diatomeas de Texcala, Puebla
Authors: Ibarra Vázquez Claudia , Novelo Eberto
Published: January 2019

57 species a n d infraspecific taxa belong to 17 genus of diatoms from a creek in Texcala, near  Tehuacan  City, Puebla,  Mexico are registered.  Six taxa not reported before from Mexico are illustrated and escribed with notes of some eco logical characteristics and   their geographical distribution. The new  records are:  Cocconeis scutellum var.  parva (Grunow) Cleve,  Cymbella turgidula  Grunow, Navicula recens Lange Bertalot, Pleurosigma salinarum (Grunow), Nitzschia calida Grunow, Nitzschia constricta (Kützing)  Ralfs.
Musgos mexicanos: una flora de transición en el Continente Americano
Authors: Delgadillo-M. Claudio
Published: January 2019

The Mexican moss  flora, with  about 967  species and  varieties,  is essentially  neotropical in character,  but  it also contains numerous boreal, southern and  widely distributed taxa; their world  and  local   ranges suggest that Mexico is the  site  of convergence of  tropical and  temperate floras that segregate altitudinally along the  mountains and are separated latitudinally by the Neovolcanic Belt. The southern part of the country contains  mostly  tropical taxa  whose distribution may extend  northward beyond 20°N  along the  coastal plains.
Los Quelites de la Sierra Norte de Puebla, México: Inventario y formas de preparación
Authors: Basurto-Peña Francisco , Martínez-Alfaro Miguel Angel , Villalobos-Contreras Genoveva
Published: January 2019

The Sierra Norte de Puebla, is a region with cultural and environmental diversity where traditional agriculture is practiced. The use of plants is vast, with more than 600 species of useful plants. The 'quelites' (edible greens), constitute between 18%-38% of edible plants and there are in total 80 species, 15 of which are exotic. The quelites can be consumed row, although they are commonly consumed after being cooked in different manners; plants parts used as quelites are young leaves and stems, sprouts, petioles, seedlings or complete plants without roots. The 'quelites' are produced in different agroecosystems under a wide spectrum of ways of management, from gathering to cultivation. The botanical families with more species used as 'quelites' are Fabaceae, Cucurbitaceae, Solanaceae, Piperaceae, Amaranthaceae and Begoniaceae. Sorne species are sold in local markets and another are for autosupply.
El effecto del microambiente en la conductividad estomática de Buddleia cordata H. B. K., en la Reserva del Pedregal de San Ángel
Authors: Ramos-Vázquez Alfredo , Barradas Víctor L.
Published: January 2019

Precipitation seasonality and substratum in Pedregal de San Angel can play a key role on plant water status. Therefore, stomatal conductance (g), water potential (? h), photosynthetically photon flux density (Q), air temperature (Ta) and leaf-air vapour pressure difference (VPD), were measured on leaves of Buddleia cordata H.B.K., because its perennial character and its dominance in the Pedregal. These measurements were carried out during the wet and dry seasons in the Pedregal which is a plant community developing in a lava substratum. The highest values of stomatal conductance were registered in the wet season (330 mmol m-2 s-1), however during the dry season, stomatal conductance was reduced by 54%. Upper limit enveloping curve technique and multiple regression analysis were performed to the data in order to study how g responded to the microenvironment and (? h). Results clearly showed that there was a significant effect of Q, Ta and VPD on g and stomata were more sensitive on humid season than during dry season. (? h), effect was not significant during the humid season, nor the dry season, but annually. Results from these kind of analysis may be very useful during the formulation of mathematics models to simulate or predict stomatal conductance.
Uso y manejo de Ibervillea millspaughii (Cogn.) C. Jeffrey, Melothria pendula L. y otras especies silvestres de la familia Cucurbitacea: Posibles procesos de domesticación incipiente
Authors: Lira Rafael , Casas Alejandro
Published: January 2019

Information on use and management of wild species of Cucurbitaceae is presented, in order to analyze processes of incipient plant domestication. Ibervillea millspaughii is a perennial plant species with massive roots, distributed from Tamaulipas to Belize. Roots of this species are utilized as medicine in the treatment of arthritis, inflammations and muscular pain. Roots are commonly collected from individuals in wild populations, but, in some villages of Quinatana Roo people tolerate and enhance individuals of this plant species in anthropogenic areas; also, people cultivate this plant species in home gardens. Melothria pendula is distributed from the United States to Argentina. Fruits and young stems and leaves of this species are consumed as food and used in traditional medicine. These products are generally gathered from wild or weedy populations, but in La Montaña de Guerrero region, the tolerance of this species and the intentional dispersion of its seeds in anthropogenic areas are also common, in order to increase its availability. Use and propagation of this plant species may involve selection by people who distinguish between "bitter" and "sweet" variants, preferring the "sweet" ones. Sicyos parviflorus, Cyclanthera dissecta, C. langaei and C. ribiflora are consumed as greens by people in different regions of Mexico, who gather them from wild or weedy populations, although individual plants of these species are also tolerated in anthropogenic areas. The different forms of management identified in the species mentioned are possibly causing processes of domestication, but such processes are yet to be evaluated.
Diversidad del cocotero en México y su evaluación al amarillamiento letal
Authors: Zizumbo-Villareal Daniel
Published: January 2019

The genetic diversity of Cocos nucifera L. is described, based on historical, and ethnobotanical studies and it is evaluated by analyzing patterns of morphological variation of fruit, variation in morpho-physiology of plants and leaves, and iso-enzyme polymorphism. Genetic structure of populations was analyzed and evaluated in relation with Lethal Yellowing disease for seven years. The diversity includes four ecotypes of tall coconut: 'Atlantic Tall', 'Pacific Tall l ', Pacific Tall 2', and 'Pacific Tall 3', and one ecotype of dwarf coconut: 'Malayan Dwarf'. Results suggest several early introductions of tall ecotypes to Mexico that were already differentiated. The genetic distance observed between Mexican populations and recently imported ecotypes suggest that the 'Atlantic Tall' originated from the west coast of Africa, while the 'Pacific Tall' ecotypes originated in the Pacific Islands, the 'Malayan Dwarf' ecotype provenances from South-East Asia. Levels of diversity in the Mexican population were similar to those of the area of New Guinea and to the collection ofthe Ivory Coast. The diversity found was exposed to Lethal Yellowing disease over a period of seven years. The 'Atlantic Tall' ecotype showed a high susceptibility, the 'Pacific Tall 3' medium susceptibility, the Pacific Tall 1 and 'Pacific Tall 2' medium resistance while the 'Malayan Dwarf' showed high resistance. It is necessary to implement a program of conservation for the ecotypes 'Atlantic Tall' and 'Pacific Tall 3', and to initiate a breeding program of crosses between 'Pacific Tall 2' with 'Malayan Dwarf' aimed at obtaining genotypesresistant to Lethal Yellowing disease which will increase productivity.
La sistemática de nuestro tiempo: Hechos, problemas y orientaciones
Authors: Crisci Jorge V.
Published: January 2019

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La conservación de la biodiversidad en México: Mitos y realidades
Authors: Gómez-Pompa Arturo
Published: January 2019

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Anatomía de la corteza de tres especies de leguminosas I. Origen y desarrollo
Authors: Orduño-Cruz Andrés , Terrazas Teresa
Published: January 2019

Origin and development of bark Pithecellobium dulce, Acacia  cochliacantha and A. farnesiana were studied anatomically. The periderm in the three species has a subepidermic origin, near the apex of the branches formed during the present growth season. Fast periderm development probably has ecological adaptations, since periderm protects from high temperatures and diseccation and also may act as an alternative photosynthetic tissue during the deciduous season. Species described show a thin, fibrous bark, generally smooth with abundant lenticels and distinctive odor. They possess sieve tube members arranged in groups or members solitary with compound sieve plate, axial parenchyma diffuse or in bands, fibers arranged in bands, and some dilated rays. They form a single periderm, without rhytidome. These characteristics are shared with other legumes, but they are distinctive by their ray size
Producción de estructuras reproductivas y fenología reproductuva de cinco especies de compuestas en una comunidad xerófita
Authors: Figueroa-Castro Dulce María , Cano-Santana Zenón , Camacho-Castillo Edgar
Published: January 2019

We studied the production of reproductive structures and the reproductive phenology of five Compositae species in a xeric community in Central Mexico: Eupatorium petiolare, Tagetes lunulata, Senecio praecox, Dahlia coccinea and Verbesina virgata. The last three species were studied in two sites with contrasting light conditions. The number of reproductive structures produced by D. coccinea was higher in the open site than in the shaded one. In contrast, S.praecox had a higher production in the shaded site, but V. virgata showed no differences. The reproductive phenology of V. virgata and D. coccinea was different between sites, but it was not happen in S. praecox. The species that flowered during the dry season had a shorter reproductive period (E. petiolare: 2.8 mo; S. praecox: 2.0 mo) than those that flowered during the rainy season or during the late rainy season (D. coccinea: 11.0 mo; T. lunulala: 8.5 mo; V. virgata: 8.5 mo) , which was caused by the high duration of the mature fruit stage in these species.
Florística del bosque mesófilo de montaña de Molocotlán, Molango-Xochicoatlán, Hidalgo, México
Authors: Mayorga-Saucedo Rafael , Luna-Vega Isolda , Alcántara-Ayala Othón
Published: January 2019

The cloud forest of Molocotlán indudes part of two municipalities of the Hidalgo State, Molango and Xochicoatlán, and is located in the Huasteca region in the Sierra Madre Oriental. Arboreal vegetation is divided in three vertical strata: high (20-30 m), medium (8-20 m) , and lower (2 -8 m). The flora of the area includes 391 species, 270 genera, and 112 families. Genera are grouped according to their present distribution in six categories; a high percentaje of them are exclusively American.
Hacia un nuevo código de nomenclatura biológica: el biocódigo
Authors: Sosa Victoria , Guerrero José A. , Flores-Castorena Álvaro , Martínez-Alvarado Domitila , Acevedo-Rosas Raúl , Aguilar-Ortigoza Carlos
Published: January 2019

In 1991 a proposal to establish a new code of biological nomenclature (BioCode) which would have preeminence over existing codes of nomenclature for virology, bacteriology, botany and zoology, was presented. The BioCocle was proposed to prescribe universal nomenclature terminology and to resolve conflicts among the existing codes. This paper compares the main rules of the botanical, zoological and the bionomenclature codes. It discusses the main changes of nomenclature rules that plant taxonomists would have to accept if the BioCocle is approved. It also presents the controversy among different groups of plant taxonomists regarding several articles of the BioCocl e. Most controversial changes proposed by the BioCocle are: abandon of Latin for diagnoses, mandatory registration of new names, new nomenclature terminology, authority and homonyms.
Genética evolutiva del proceso de domesticación en plantas
Authors: Rendón Beatriz , Núñez-Farfán Juan
Published: January 2019

Studies about the incipient domestication in plants often have based their analysis on morphological characteristics and have attributed those changes to the actions of artificial human selection. This paper remarks the importance of the analysis of incipient domestication in plants using the theoretical and methodological framework of both quantitative and population genetics. The premise of this work is that, considering domestication as an evolutionary process, much knowledge can be gained regarding the phenotypic change, its constraints, and the evolutionary mechanisms that have molded the genetic constitution of plant populations under domestication.
La sistemática de cactáceas en México, breve recuento y perspectivas
Authors: Arias Salvador
Published: January 2019

A summary on systematics knowledge of Cactaceae in Mexico is presented. It provides a bibliographic revision of the development in systematics studies and its main areas of research, as monographic revisions, floristics, anatomical, palynological, embryological and biochemical, as well as the contributions made by Mexicans. Advances in those disciplines and in the new systematics methodologies show a clear and evident inter relationship to a better understanding about classification and phylogeny of Cactaceae. Finally, this paper points out some perspectives in relation to research collections, collaborations and personnel training.
Ordenación de las poblaciones silvestres de pitayo y cardón en la Cuenca de Sayula, Jalisco
Authors: Huerta-Martínez Francisco Martín , García-Moya Edmundo , Flores-Flores José Luis , Pimienta Barrios Eulogio
Published: January 2019

The ecological relationships of "pitayo" and "cardón" were studied in the Sayula, Jalisco Basin. A multivariate approach was used considering three sets of explanatory variables: geographical (FG), edaphic (E) and biotic (B). Three columnar cacti species Stenocereus queretaroensis, and S. dumortieri and Pachycereus grandis were found. According to a detrended correspondence analysis the length of the gradient was 3.59 S.D., which justifies the use of unimodal response model for the species data. Also the results of a correspondence analysis showed a sites and species pattern related to a supposed moisture gradient. Due to the presence of outliers in some variables, it was necessary to use certain passive sites in the canonical correspondence analysis. The selected variables were: a] geographical: latitude, longitude, elevation and exposure; b] edaphic: potassium content, cation exchange capacity and sand percentage. Of these components of species data variation, the first explains 28.94% and the second one 23.66%, while the interaction of both explains only 8.23%. At the biotic level, the accompanying shrubs and tree species data were related to "pitayo" and "cardón" attributes in two ways: a] as three separated populations, or b] as a complex. The better selected attributes were total cover and average height of individual in the complex, or else S. dumortieri and P. grandis, respectively, for the species strategy. However, there was a poor relation for the species (17.4%), with the variation of the associated shrub and tree species.
Distribución del manglar en cuatro sistemas lagunares en la costa de Chiapas, México
Authors: Montes Cartas Claudia Gabriela , Castillo-Argüero Silvia , López-Portillo Jorge
Published: January 2019

Mangrove plant group distribution was stuclied along the Chiapas Coast by means of 177, 10 m x 10 m quadrats taken in 16 sites in the four most important lagoon systems. To classify the quadrats by importance values permited us to distinguish eight mangrove groups. Around 73% of the total variance of the quantitative data was accounted by the first two principal axes in the ordination of quadrats. The first axis was significantly associated to the field salinity (r=-0.76, g. l.=15, p<0.001), which decreases from NW to SE as a consequence of the amount of water continental runoff. Finally, it was found that the height of Laguncularia racemosa (r=0.56, g. l. =60, p=0.0001) and Rhizophora mangle (r=0.59 , g. l. =124, p=0.0001) , but Avicennia germinans (r=0.24, g. l.=47, p=0.09), were inversely related with salinity concentration and with the contribution of freshwater from the drainage systems corresponding to each coastal lagoon system.