Analyses of richness and endemism of Cyatheales (tree ferns) in tropical America were performed and evidence of a diversity gradient is presented. For this, the occurrence ranges of 239 species were plotted into a 5°9 5°grid-cell map and then analyzed using species richness and endemism indices. Here we show that species richness and endemism are not distributed randomly over the landscape, but do aggregate into defined regions of high diversity in tropical America: the northern Andes, lower Central America, upper Central America and Mexico, the Guyana Highlands, southeastern Brazil, and the Antilles. These distributional patterns are congruent with the geographical distribution of cloud forest, which in turn is determined by topography, high humidity, and persistent cloud immersion. The mountain regions of tropical America, especially the cloud forests, harbour most of the species of American Cyatheales and have high levels of habitat loss and climatic fragility. Conservation policies for Cyatheales are centred on the local use and trade of many tree fern species, but none such policies focus on cloud forest habitat loss. This makes tree ferns a critically endangered group of plants. In the face of the current environmental crisis and global climate change, the presence of Cyatheales in these regions sounds the alarm on their conservation priorities.Electronic supplementary material The online version of this article (

The objective of the present study was to document the richness and distribution of the pteridoflora in the plant communities of the National Park Los Mármoles, the second largest natural protected area and the largest in Hidalgo. The study was based on exhaustive collection of specimens in different types of vegetation. Eleven families, 28 genera and 65 species of ferns were found, and one family with six species of lycopods. Seven taxa not previously mentioned for the state of Hidalgo are cited: <em>Anemia mexicana var. makrinii, Argyrochosma palmeri, Cheilanthes spiculata, Pecluma alfredii var. cupreolepis, Polypodium puberulum, Selaginella sartorii and S. wrightii. </em>

En este trabajo se reportan los resultados de un estudio experimental que se llevó a cabo para promover la motivación en estudiantes universitarios para participar en un curso de botánica. El estudio consistió en evaluar una estrategia educativa diseñada ex profeso para mejorar la enseñanza de la disciplina a partir de un módulo introductorio, enfocado a desarrollar en los estudiantes intereses y actitudes favorables al aprendizaje de los contenidos de la asignatura. Para valorar la estrategia se evaluaron los conocimientos, opiniones y actitudes de los alumnos antes y después del curso. Los resultados muestran que hubo cambios significativos de acuerdo a lo esperado con la hipótesis de trabajo.

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