In Mexico, ultramafic complexes are present in different regions from the northwest (Baja California Norte) to the southeast (Chiapas). In this paper, we present the results of the exploration of three ultramafic (serpentine) habitats in central and southern Mexico: Cuicatlán–Concepción Pápalo (Oaxaca), Tehuitzingo–Tecomatlán (Puebla), and San Juan de Otates (Guanajuato). Previous geology studies showed that these complexes are mainly made up of serpentinized peridotites. Soil analyses demonstrated typical ultramafic characteristics such as high content of Mg in relation to Ca, and high concentrations of Fe, Cr, Co, and Ni. Soil samples from Oaxaca and Puebla had similar Ni contents around 2300 mg kg−1, while samples of Guanajuato showed the lowest Ni levels with an average of 200 mg kg−1 as well as for other metals such as Co, Cr, Mn, and Zn. During this study, 83 plant specimens were collected, of which 52 were identified at genus level and 40 at species level. The collected plants belong to 19 different families such as Anacardiaceae, Fabaceae, Acanthaceae, Asteraceae, Sterculiaceae, and Verbenaceae which are also widely present in other ultramafic areas in Iran, Brazil, Sri Lanka, and Costa Rica. Only two Mexican endemic species are included in the collection. Ni hyperaccumulators were not detected at any of the studied sites. Therefore, hyperaccumulation, as a tolerance mechanism of the flora in response to ultramafic geochemical stress, does not seem to be developed in Central Mexico, as observed in the close Costa Rican site of Santa Elena.

Diospyros (Ebenaceae) está conformado por alrededor de 500 especies, 120 están en América y más de 20 en México. Su distribución es tropical y se sostiene que se originó en Gondwana occidental. Este estudio es un análisis de la distribución geográfica de 1 452 sitios de colecta de 20 especies integrados en Global Biodiversity Information Facility(GBIF),con unenfoquepanbiogeográfico;aplicando un método combinado para el análisis de trazos y dos análisis de parsimonia de endemismos asociados al mapa de regiones bioeográficas de México y al de tipos de vegetación. La distribución principal del género es en el centro y sur del país constituyendo un elemento típicamente neotropical. Utilizando los trazos individuales se obtuvieron dos nodos principales, el primero en el centro de Veracruz y el segundo en el nororiente de la península de Yucatán. El análisis de parsimonia agrupa a las provincias de Yucatán, Petén, Golfo de México, Depresión del Balsas, Costa del Pacífico, Sierra Madre Oriental, Eje Volcánico Transversal, Sierra Madre del Sur, Oaxaca y Altiplano Zacatecano-Potosino en un sólo grupo. Este grupo concuerda con el dominio Mesoamericano y Antillano y con el dominio Mexicano de Montaña o Zona de Transición Mexicana. El análisis de los sitios de presencia evidenció a los bosques tropicales como grupos basales. Los resultados soportan la tesis de su origen e ideas sobre su diversificación geográfica y biológica, involucrando eventos dispersalistas y vicariantes, relacionados con eventos geológicos como la formación del Eje Volcánico Transversal. La mayoría de estas especies son de amplia distribución ya que se encuentran en más de una provincia, siendo la Costa del Pacífico, el Golfo de México y el Eje Volcánico las que cuentan con mayor riqueza: 12 especies cada una. Se postula que Diospyros concuerda con la migración de especies de la región Neotropical hacia la Zona de Transición Mexicana.

kindly supplied a hand-held XRF instrument for herbarium scanning. This research was partly undertaken at P06 at at Deutsches Elektronen Synchrotron (DESY), a member of the Helmholtz Association (HGF). The research leading to this result has been also supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. The micro-XRF instrumentation used in this study was cofunded by ICEEL (Carnot Institute)-CREGU-LabEX Ressources 21 (ANR-10-LABX 21-LABEX RESSOURCES 21) and FEDER. Special acknowledgments are made to MSc Blanca V. Juarez Jaimes (MEXU herbarium) for plant identification, to MSc. Jorge A. Ramírez Espinosa, Ing. Francisco Navarrete Torralba and all the students from the Universidad Tecnológica de la Selva (UTS) for their valuable contribution during the field surveys and for their current investment in this research. The authors are also grateful to Haley Disinger for the enrichment of the database (XRF screening data from the MO herbarium in Saint Louis), to Vanessa Invernon for her support at the Paris herbarium (Muséum National d'Histoire Naturelle in Paris) and to all the technicians from MEXU herbarium for their valuable cooperation.We would like to thank Kathryn Spiers and Jan Garrevoet for their assistance during the experiments.We wish to thank Professor Alan Baker (The Universities of Melbourne and Queensland, Australia) for reviewing the paper and suggesting improvements to the text.

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vesicatory (Xcv) phytopathogenic bacteria, with extracts of different polarity obtained from roots of Jatropha dioica Seseé (Blood grade), endemic plant species of Mexico valued in traditional medicine for its pharmacological and healing properties. As an indicator of cellular respiration in bacterial cultures exposed to extracts, 2,3,5-triphenyltetrazolium chloride was used. The methanolic, hexane and ethyl acetate extracts showed antimicrobial activity against the phytopathogens Cmm, Pst and Xcv. According to the results, the hexane extract showed the lowest Maximum Average Inhibitory concentration (IC50) against Pst and Xcv (0.5 ± 0.01 and 1.7 ± 0.36 mg mL-1 , respectively), so it was separated by column chromatography. As a result, a white crystalline solid identified spectroscopically as citlalitrione was isolated and purified, said compound also exhibited activity against the Cmm, Pst and Xcv bacteria with an IC50 of 1.0 ± 0.13, 1.0 ± 0.11 and 1.1 ± 0.19 mg mL-1 , respectively. These in vitro results open the possibility of using plant extracts of J. dioica for the control of diseases caused by the bacteria studied in tomato cultivation, offering an alternative to the use of antibiotics or copper compounds.