Agrostis is one of the most diverse genera of the Poaceae, including ca. 198 species, principally distributed in cold and temperate regions of the world, but also found in the high mountains of the tropics. We present a revision based on morphoanatomical evidence, for the biogeographic region known as Megamexico 3 (i.e., Mexico including the desert areas of southern USA and the Central America territory, to northern Nicaragua). We include taxonomic descriptions and an identification key for the found taxa, maps with the known geographical distribution of the species, and figures with the morphoanatomical characteristics, elevation and phenology. Agrostis is represented in the study zone by 20 species, of which four are endemic and three are introduced. Most records of the genus are distributed in the mountains, above 1500 m a.s.l., in open areas of temperate forests, with conifers and Quercus. Specimens with spikelets occur year round, but most records occur during the wet season, in the months of July to October. We propose a preliminary conservation assessment for each species in the study zone, according to the International Union for Conservation of Nature categories: one with Deficient Data (DD), six as Endangered (EN), two as Vulnerable (VU), and 11 as Least Concern (LC).

Antecedentes: La familia Apocynaceae está entre las 13 más diversas de México y su conocimiento taxonómico ha tenido una atención creciente con la implementación de filogenias y otras herramientas para resolver su sistemática. Con más de 10 años del último listado enfocado en la familia, resulta necesario actualizar el conocimiento sistemático del grupo. Pregunta: ¿Cómo se ha consolidado hasta nuestros días el conocimiento sistemático del grupo en México? ¿Cómo ha cambiado el número de géneros y especies de Apocynaceae en el país y su distribución geográfica por estado? Especie de estudio: Apocynaceae Sitio de estudio: México Método: Revisión de herbarios nacionales e internacionales, bases de datos y una búsqueda intensiva de literatura. Así como colectas en diferentes partes del país. Resultados: Apocynaceae presenta 52 géneros y 418 especies nativas, 204 de ellas endémicas. La subfamilia Asclepiadoideae destaca con 27 géneros y 314 especies. Los estados con más especies y endemismos son Oaxaca, Chiapas, Veracruz y Guerrero. Los estados con más microendemismos son Oaxaca (18 spp.), Chiapas y Jalisco (6 spp.), Baja California Sur y Veracruz (5 spp.). Se proporciona una clave de géneros y un listado actualizado. Conclusiones: Apocynaceae se ubica en el lugar número 12 de las familias más diversas del país. Esto reitera al país como un centro de diversidad del grupo. La integración de más estudios relacionados a la aplicación de herramientas filogenéticas, modelos de distribución y redes de interacción biológica permitirá entender mejor a la familia y proporcionar una historia natural más completa.

Background: Mexico is a megadiverse country with an elevated diversity of species of vascular plants. A comprehensive Flora that includes all of the vascular plants distributed in Mexico does not yet exist. Electronic Floras have demonstrated the value of a compendium based on existing knowledge and published Floras, checklists and revisions. Questions: What is the best approach for publishing the Flora of Mexico? What resources are needed to create this Flora? What is the current status of these resources? Objective: The objective of this paper is to summarize and evaluate the taxonomic and digital resources and the bioinformatic tools needed to develop an online Flora for the vascular plants of Mexico, as well as to discuss its content. Results and Conclusions: An online flora using the EDIT Platform for Cybertaxonomy is proposed, with the collaboration of Mexican and international researchers. It will be based on approximately 5.3 million specimens deposited in Mexican herbaria, with an inter-operational portal to other biodiversity platforms. The name assigned to this online flora is “eFloraMEX”. As a starting point, the taxonomic backbone, the checklist for the Mexican vascular plants including approximately 29,000 species, was published in a portal (efloramex.ib.unam.mx) to be revised and updated by specialists. A council of taxonomists and computer experts will lead the eFloraMEX project on two fronts: taxonomic and digital resources. The main challenges to completing this Flora are building the team, training taxonomists, digitizing the specimens for most of Mexican herbaria and obtaining the required long-term funding.

Background and Aims: Recent studies have focused on resolving the systematics of the tribe Gonolobinae of the family Apocynaceae, as well as the controversial genus Matelea s.l. However, many species within Matelea s.l. have not been evaluated phylogenetically. This is the case of M. gonoloboides, previously recognized as the type species of Urostephanus, and other taxa with similar floral morphology. The aim of this study is to test the monophyly of Urostephanus, including some species with morphology similar to M. gonoloboides. Furthermore, we evaluate the taxonomic position of the Urostephanus clade within the subtribe Gonolobinae and compare morphology among related clades. Methods: To assess phylogenetic relationships within Gonolobinae, we downloaded sequences from four loci for 94 species of the subtribe from GenBank. We extracted DNA and sequenced the trnL-F intergenic spacer and rps16 intron from four species of Dictyanthus and six species of Matelea, which are considered to belong to Urostephanus. We reconstructed the phylogeny with Bayesian inference using the maximum clade credibility tree. Based on the phylogenetic pattern, we performed morphological comparisons between the clades Dictyanthus, Polystemma, and Urostephanus. Key results: Phylogenetic analysis recovered Urostephanus as monophyletic and sister to Dictyanthus. Based on this phylogenetic pattern and floral morphology, we resurrect the genus Urostephanus. We propose eight new combinations for the species included in the phylogeny, as well as for those that share floral morphological similarity. We designate two lectotypes. Finally, we discuss aspects of morphology between Urostephanus and closely related groups. Conclusions: The current circumscription of Matelea s.l. includes species with high morphological diversity. With the phylogenetic and morphological evidence among related taxa, we support the resurrection of Urostephanus, more than 120 years after its description. These results contribute to the resolution of the systematics of Gonolobinae in Mesoamerica. Antecedentes y Objetivos: Estudios recientes se han centrado en resolver la sistemática de la tribu Gonolobinae, así como del controversial género Matelea s.l. Sin embargo, varias especies dentro de Matelea s.l. no han sido evaluadas. Tal es el caso de Matelea gonoloboides, previamente reconocida como especie tipo de Urostephanus, y otras especies con una morfología floral similar no han sido evaluadas filogenéticamente. Los objetivos de este estudio son probar la monofilia del grupo Urostephanus, incluyendo algunos taxones con morfología similar a M. gonoloboides. Además, evaluamos la posición taxonómica del grupo Urostephanus dentro de la subtribu Gonolobinae y comparamos la morfología entre clados afines. Métodos: Para evaluar las relaciones filogenéticas dentro de Gonolobinae, descargamos de GenBank las secuencias de cuatro loci para 94 especies de la subtribu. Extrajimos ADN y secuenciamos trnL-F y rps16 de cuatro especies de Dictyanthus y seis especies de Matelea, que se consideran en el grupo Urostephanus. Reconstruimos la filogenia con inferencia Bayesiana, empleando el árbol de máxima credibilidad de los clados. Con base en el patrón filogenético, realizamos una comparación morfológica entre los clados Dictyanthus, Polystemma y Urostephanus. Resultados clave: El análisis filogenético recupera las especies del grupo Urostephanus como monofiléticas y relacionadas con Dictyanthus. Con base en este patrón filogenético y la morfología floral, resucitamos al género Urostephanus. Proponemos ocho nuevas combinaciones para las especies incluidas en la filogenia, así como para aquellas que comparten similitud morfológica floral. Designamos dos lectotipos. Además, discutimos aspectos sobre la morfología entre Urostephanus y grupos cercanamente relacionados. Conclusiones: La circunscripción actual de Matelea incluye especies con una gran diversidad morfológica. Con la evidencia filogenética y morfológica entre taxones relacionados apoyamos la resurrección de Urostephanus, más de 120 años después de su descripción. Estos resultados contribuyen a resolver la sistemática de Gonolobinae en Mesoamérica.

Background: Aphyllon is a genus of 25 root-holoparasitic species restricted to the Americas. It has a disjunct distribution, with 21 species distributed in North America and four in South America. Aphyllon is divided into two sections: Aphyllonand Nothaphyllon. All species of the genus have host-specificity, make it a study model in the evolution of holoparasitic plants. Recently, observations of a putative new species of Aphyllon were detected on iNaturalist. Questions: Are the alluded iNaturalist observations of Aphyllon supported as a new species? What characters distinguish this taxon from the other species of Aphyllon? Studied species: Taxa of Aphyllon section Nothaphyllon. Study site and dates: Mexico; 2020–2023. Methods: Specimens were collected, dissected, measured, photographed and preserved. Herbarium specimens and literature on Aphyllon were reviewed. Comparisons of the taxon with species of section Nothaphyllon’s were performed. Results: A new species of the holoparasitic Aphyllon (Orobanchaceae) is described and illustrated. It is the second species of tropical humid vegetation in Mexico, an atypical environment for most of the genus, and it is the only species of the section with racemes with narrowed to nearly closed corolla mouths, and straight, non-revolute lobes of the lower lip. Conclusions: The records in the citizen science platform have been useful to illustrate the morphology and color of the organisms, as well as to propose new species of Aphyllon. The photographs provide information not found in herbarium specimens due to oxidation and discoloration that occurs when drying Orobanchaceae plants.