A list of 618 species of alien flowering plants recorded for Mexico is presented; they are distributed in 355 genera and 87 families. The families with the largest number of species are Poaceae (171), Fabaceae sensu lato (57), Asteraceae (56), and Brassicaceae (45). The representation of most families with alien species in Mexico agrees with the average distribution frequencies estimated by Pysek (1998) for 26 floras throughout the World. Exceptions are an under‐representation of Asteraceae and an over‐representation of Poaceae. Most alien species (78.9%) in Mexico have their origin in the Old World; South America ranks second with 9.6%. As defined by Richardson et al. (2000), 19.8% of the alien species could be considered casual aliens and 80.2% of them naturalized. The proportion of alien species relative to the 22,968 native flowering plant species recorded for Mexico is 2.7%.

Over the past 20 years, the biodiversity associated with shaded coffee plantations and the role of diverse agroforestry types in biodiversity conservation and environmental services have been topics of debate. Endophytic fungi, which are microorganisms that inhabit plant tissues in an asymptomatic manner, form a part of the biodiversity associated with coffee plants. Studies on the endophytic fungi communities of cultivable host plants have shown variability among farming regions; however, the variability in fungal endophytic communities of coffee plants among different coffee agroforestry systems is still poorly understood. As such, we analyzed the diversity and communities of foliar endophytic fungi inhabiting Coffea arabica plants growing in the rustic plantations and simple polycultures of two regions in the center of Veracruz, Mexico. The endophytic fungi isolates were identified by their morphological traits, and the majority of identified species correspond to species of fungi previously reported as endophytes of coffee leaves. We analyzed and compared the colonization rates, diversity, and communities of endophytes found in the different agroforestry systems and in the different regions. Although the endophytic diversity was not fully recovered, we found differences in the abundance and diversity of endophytes among the coffee regions and differences in richness between the two different agroforestry systems of each region. No consistent pattern of community similarity was found between the coffee agroforestry systems, but we found that rustic plantations shared the highest number of morphospecies. The results suggest that endophyte abundance, richness, diversity, and communities may be influenced predominantly by coffee region, and to a lesser extent, by the agroforestry system. Our results contribute to the knowledge of the relationships between agroforestry systems and biodiversity conservation and provide information regarding some endophytic fungi and their communities as potential management tools against coffee plant pests and pathogens.

The genetic diversity of Mesoamerican populations of the biofuel plant Jatropha curcas, using the fatty acids of the seeds as chemical markers was studied. The oil content of the whole seed in 135 accessions from 38 sites varied between 8.020% and 54.28%. The prevalent fatty acids were oleic acid (18:1) and linoleic acid (18:2), and the proportion of unsaturated fatty acids varied between 74.5% and 83.7%. A study with cloned plants grown in common garden showed that both the content of oil as well as the proportion of fatty acids are highly inheritable, therefore these chemical markers are valid for estimating the genetic diversity of the species. An analysis of principal components showed that the fatty acids that contribute more to the variance are stearic, oleic, linoleic, methylpalmitic, gadoleic and ricinoleic. The populations were classified in ten groups when the data were analyzed for fatty acids by analysis of clusters, showing the elevated genetic variation in natural populations of this native species of Mesoamerica. A discriminant analysis separated the populations in accordance with their geographic origin, which was verified with a Mantel test. Using the Monmonier’s algorithm two genetic barriers between the populations were identified. The results are discussed in light of their microevolutionary significance.