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Impatiens mexicana is a native balsam restricted to the cloud forests of central and southwest Mexico, which is currently known to exist in four states (Zacatecas, Veracruz, Puebla, and Oaxaca), and is probably threatened by geographic restriction. Morphological and distributional information about this species is still scarce, with only a couple of investigations since its first description in 1910, which means the phylogenetic position of this species has yet to be placed. In order to contribute to knowledge of I. mexicana, morphological and molecular studies were carried out with material collected in the localities of Hidalgo, Veracruz, and Oaxaca, during expeditions from July to October 2021 and in 2022. The specimens selected were measured, photographed, and compared with morphological information from the six American balsams. At the same time, phylogenetic studies were carried out by using two regions of the cpDNA and one of the nrDNA. We report I. mexicana for the first time in Hidalgo state, and identify new registers in the Veracruz and Oaxaca localities, thus increasing the knowledge in its geographic distribution. We also redescribe the Mexican balsam by using new and complementary traits: we note that while the species is morphologically similar to I. capensis, it is distinguished by differences in flower color, the distribution of spot patterns on the upper petal, lower sepal, and lateral petals, and geographic information such as endemic geographic distribution in Mexico's Tropical Montane Cloud Forest (TMCF). We also carried out phylogenetic analyses by using ITS and ITS + atpb-rbcL, which showed the Mexican balsam was independent from its Asian-American congeners. Interestingly, our genetic distance analyses reveal differences of 0.01–0.16% between I. mexicana and the other North American congeners that use ITS, atpb-rbcL and trnL-F, both independently and as concatenated genes: this low divergence most likely occurred because of the recent diversification of the group. However, both future redescriptions and phylogenetic studies in American species are imperative, as this will enable better discrimination. [ABSTRACT FROM AUTHOR]

The agaves are plants of cultural importance which have been used by humans for about 10,000 years and about 40 specific uses. The most culturally and economically important of those uses are for the production of fermented (pulque) and distilled beverages (mescal). Pulque continues to be produced in nearly all of Mexico, and the agaves used for this purpose have shown domestication syndrome. We carry out an ethnobotanical, morphological, and genetic analysis of the traditional varieties of pulque agave used in the production of aguamiel (agave sap) and pulque in the state of Hidalgo. We did semi-structured interviews, free listings, and tours with 11 agave managers. We analyzed morphology and studied genetic diversity and structure using nuclear microsatellites. We found wild-collected, tolerated, transplanted, and cultivated varieties of agave. This comprised 19 traditional varieties of pulque agave, 12 of them in production during the study, which corresponded to the species Agave americana, A. salmiana y A. mapisaga and five intraspecific entities. The varieties were grouped morphologically according to a management gradient; the wild-collected varieties were the smallest, with more lateral teeth and a larger terminal spine. The cultivated varieties clearly exhibited domestication syndrome, with larger plants and smaller dentition. The expected heterozygosity (He) of the varieties ranged from 0.204 to 0.721. Bayesian clustering suggested the existence of three genetic groups, both at the level of traditional varieties of pulque agaves and for management categories, a result that matches multivariate clustering. Pulque producers in the studied localities maintain high agrobiodiversity. The cultivated varieties exhibit domestication syndrome, as has been reported for other species of the genus with the same selection purposes. Our results support the hypothesis of a decrease in genetic diversity in crops compared to wild-growing agaves, which seems to be due to vegetative propagation, among other factors. [ABSTRACT FROM AUTHOR]