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Background: The Sayula sub-basin presents a complex landscape composed of plants communities that to date have not been studied in a timely manner, so this study contributes to the knowledge of the flora and vegetation of the area and the State.Question: i) How many and which families, genera and species are in the Sayula sub-basin? ii) What are the main biological forms of the species? iii) Are there species under any category of protection? iv) How many vegetation types are present within the region?Studied species: Ferns, Gymnosperms and Angiosperms. Study site and years of study: The Sayula sub-basin, Jalisco, Mexico; from February 2012 to October 2015. Methods: Through the literature review and field work the floristic checklist was elaborated. In addition, with the use of geographic information systems, a map of land use and vegetation was made.Results: A total of 687 species were recorded, including 415 genera and 113 families. The five main families were Poaceae, Asteraceae, Fabaceae Solanaceae and Euphorbiaceae representing 42.6 % of the total species and 36.6 % of the genera. It should be noted that the predominant biological forms were herbs with 409, 105 shrubs and 74 trees. On the other hand, 47 species registered under some protection category of which, only one species Cleomella jaliscensis is endemic to the region. Finally, eight vegetation types were determined, being the tropical deciduous forest the one that occupies greater surface and presents greater floristic diversity. Conclusions:It is important to emphasize that during the realization of the work, agricultural activities were detected affecting the flora and vegetation, threatening the biodiversity and the natural balance of the region.Key words: Floristic richness, phytogeography, plant communities, western Mexico. ResumenAntecedentes: La subcuenca Sayula, presenta un complejo paisaje conformado de comunidades vegetales que a la fecha, no han sido estudiadas de manera puntual, por lo que este estudio contribuye al conocimiento de la flora y vegetación de la zona y del Estado.Pregunta: i) ¿Cuántas y cuáles familias, géneros y especies se encuentran en la Subcuenca Sayula? ii) ¿Cuales son las principales formas biológicas que presentan las especies? iii) ¿Existen especies bajo alguna categoría de protección? iv) ¿Cuantos tipos de vegetación se presentan dentro de la región? Especies de estudio: Helechos, Gimnospermas y Angiospermas. Sitios de estudio y años de estudio: La subcuenca Sayula, Jalisco, México; desde febrero de 2012 hasta octubre de 2015.Métodos: Mediante la revisión de literatura y trabajo de campo se elaboró el listado florístico. Además, con el uso de sistemas de información geográfica se realizó un mapa de uso de suelo y vegetación.Resultados: Se registraron un total de 687 especies, incluidas en 415 géneros y 113 familias. Las cinco principales familias fueron Poaceae, Asteraceae, Fabaceae Solanaceae y Euphorbiaceae que representan el 42.6 % del total de las especies y el 36.6 % de los géneros. Cabe resaltar que ...

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Background The poorly developed soils of the embryo dunes imply little capacity for plant support, however, the adaptation mechanisms of plants respond sensitively to environmental variations, even when these variations are small, which results in a set of specialized habitats and flora that are rarely shared with other terrestrial ecosystems. The coastal dunes of the Mexican Pacific remain vaguely studied, this is why this research explored the relationship between environmental properties and the presence of plant species in the embryo dunes of the coast of Jalisco, Mexico. Methods Twenty-nine sites were sampled, one or two sites per embryo dune, with a random stratified design. Geomorphological and vegetation data were collected at site. Laboratory determinations included soil color, particle size, organic matter, pH, electrical conductivity, magnetite content, and moisture retention. Statistical analysis included correlation analysis to identify relationships between environmental variables; principal component analysis (PCA) and cluster analysis to group dune sites by environmental properties; canonical correspondence analysis (CCA) to determine a possible significant relationship between the presence of plant species and environmental variables; cluster analysis to group dune sites by presence/absence of plant species and correlate both clusters to validate the relationship between them, the salient aspects of this relationship were described and the spatial distribution of the groups was mapped. Results Eleven plant species were identified, six of them exclusive to the embryo dunes and the rest ubiquitous. The incipient development of these soils is reflected in a low content of organic matter, silt, clay, and moisture retention, with scattered data on granulometry, electrical conductivity, organic matter, and magnetite. Some significant correlations were found between some environmental properties, and the CCA showed a significant relationship between the presence of plant species and environmental variables (p-value of the Monte Carlo test = 0.026). The cluster analysis of dune sites according to environmental variables and the cluster analysis by presence/absence of plant species produces the formation of five groups of sites with significant environmental differences and five groups of sites with significant floristic differences. A significant connection (r = 0.471, p = 0.01) between the two clustering schemes also evidences the meaningful relationship between the presence of plant species and the environmental characteristics of the embryo dunes of Jalisco, Mexico. Differences in habitat preferences were observed among plant species exclusive to the embryo dunes; thus, Abronia maritima, Uniola pittieri, and Pectis arenaria showed a preference for embryo dunes with poor edaphic conditions, in contrast to Okenia hypogaea, Canavalia rosea, and Scaevola plumieri, which were mostly found in embryo dunes with higher fertility.