Background: Euphorbiaceae is one of the largest angiosperm families in Mexico, but our understanding of its diversity and distribution is incomplete, and most genera lack taxonomic revisions. Questions: How many genera and species of Euphorbiaceae occur in Mexico, and which of these are endemic to the county or a particular state? Where is the greatest diversity? Study site and years of study: Mexico, 1990s-present. Methods: Pertinent Euphorbiaceae literature was reviewed, and major herbaria were consulted, as too was the iNaturalist platform. This information was supplemented by fieldwork. Results: Euphorbiaceae is the fifth most diverse family in Mexico, where 32 genera and 713 species occur natively. Eleven species and two genera (Ricinus y Mercurialis) are naturalized. Four genera contain almost 75 % of the species (Euphorbia, 245 spp., Croton, 130 spp., Acalypha 109 spp., and Jatropha 50 spp.), whereas 24 genera contain fewer than 10 species. Enriquebeltrania is the only endemic genus, but 413 (57 %) species are endemic. The family is distributed from sea level to 3,600 m and is found in nearly all types of vegetation. The states with the greatest diversity are Oaxaca (247 spp.), Jalisco (210 spp.), Chiapas (196) and Veracruz (189 spp.). Conclusions: Our taxonomic and floristic understanding of the family is incomplete, and few genera have a modern revision or monograph. Twelve species are included in the NOM-059-(SEMARNAT 2010), and an additional 77 are at risk following the criteria of the IUCN Red List. It is imperative to conduct more research on taxonomy, distribution, and conservation.

Drymaria (Caryophyllaceae) is here considered to contain 56 species plus 19 infraspecific taxa, excluding autonyms. In the current study, all effectively published names of Drymaria were compiled, and information about their taxonomy, distribution, and nomenclatural types is provided. In addition, an overview of the taxonomic history of Drymaria is presented. As a result, one neotype, 15 lectotypes, and the type for the genus Mollugophytum are newly designated. Altogether, 188 names were treated, of which 52 are heterotypic and 50 are homotypic synonyms. An additional 10 names were either unresolved or are now considered to belong to other genera. A brief assessment of the distribution of the respective taxa is also provided, including the examination of herbarium specimens and specimen images, which indicates that two regions possess high levels of endemism—Mexico with 20 species and the Andes with 14 species. There are few studies that assess the conservation status of Drymaria species, and only 10 species and two varieties have had IUCN Red List assessments.

The new species Euphorbia peruviandina (Euphorbiaceae) is described and illustrated with photos and line drawings. It belongs to subgenus Chamaesyce section Anisophyllum and is restricted to the puna vegetation of central and southern Peru at elevations of 3300 to 4200 m. It is proposed to be endangered following IUCN criteria. A comparison is made with two other Andean species of the section, E. jamesonii of Ecuador and E. orbiculata of Colombia and Venezuela. For all three taxa, type specimens are cited, and morphological descriptions, habitat information, exsiccate, and synonymy are given. An identification key to these taxa is provided. Euphorbia melanocarpa is proposed to be a synonym of E. jamesonii, and E. meridensis is treated as a synonym of E. orbiculata.

Antecedentes: A pesar de su gran diversidad y la grave amenaza a la que están expuestos, los pastizales templados han recibido escasa atención. Pregunta: Este estudio examina la biodiversidad de paisajes y taxonómía en los pastizales templados de Oaxaca. Especies estudiadas: Flora vascular. Sitio de estudio y fechas: Los pastizales volcánicos (PV), calcícolas (PC) y sabanas de encino (SE) del norte de Oaxaca entre 2021 y 2022. Métodos: Tras delimitar los tres sistemas realizamos colectas, describimos la vegetación y discutimos su estado de conservación. Resultados: Los PV y PC son los más diversos. En los PV, la diversidad se ve favorecida por el pastoreo, cuya ausencia promueve la invasión por plantas exóticas y pérdida de especies. Los PC han sufrido graves impactos debido a la agricultura, el sobrepastoreo y la plantación de pinos. Las SE son las menos diversas, aunque las menos muestreadas, y albergan especies importantes para su conservación. En total se documentaron 857 especies de plantas vasculares (aunque los datos indican que esto es una subestimación considerable), siendo el segundo pastizal más diverso de Norteamérica y comprendiendo 25 % de las especies del Valle de Tehuacán-Cuicatlán en 0.7 % de su superficie. Las familias más diversas fueron Asteraceae, Poaceae, Fabaceae, Lamiaceae y Euphorbiaceae. El 37 % de las especies son endémicas de México, algunas especies microendémicas (3) y 26 amenazadas. Además, se descubrieron tres nuevos taxones. Conclusiones: Nuestros resultados subrayan la importancia de conocer y conservar las praderas intertropicales templadas de México ante la rápida destrucción que enfrentan.

Mexico is one of the countries with the highest cultural, biological, and agrobiological diversity. However, an accelerated process of ancestral knowledge loss, related to the management of agrobiodiversity, native seeds, and other edible plant species management is affecting food sovereignty. This process of knowledge loss was documented at the Ñäñho region, of southern Querétaro, where our study took place. Our objective was to document the diversity of edible plant diversity, management, and use as well as the agroecosystems from which they are obtained. Semi-structured interviews were conducted over 2 years (2021–2023) with 50 informants selected through a snowball sampling. Informal interviews and participant observations were also used with these and other people from the same community. Herbarium specimens and seed accessions were collected and photographed. In total, 119 edible plant species were identified. The richest families were Solanaceae, Rosaceae, Cactaceae, and Asteraceae. The edible species occur in 11 agroecosystems with 58.6

Antecedentes: Dalea es endémico de América, posee amplia distribución en la provincia del Desierto Chihuahuense, sus especies se asocian a matorral xerófilo, bosque de encino y bosque de coníferas. Hipótesis: Las especies de Dalea funcionan como un subrogado de la flora y refuerzan las propuestas de regionalización para esta provincia. Sitio y años de estudio: Provincia del Desierto Chihuahuense, agosto 2020 a julio 2022. Métodos: Se elaboró una base de datos a partir de ejemplares de herbario. El análisis de riqueza de especies se realizó con una cuadricula de 1 × 1°. El endemismo ponderado (WE) y endemismo ponderado corregido (CWE) fueron estimados. Para regionalizar, el recambio de especies fue calculado y se aplicó el método de agrupación UPGMA. Para determinar la caracterización ambiental de los componentes bióticos, los grupos se cotejaron con ecorregiones publicadas. Resultados: Se encontraron 3,061 registros de 77 especies de Dalea, 33 son endémicas al área de estudio. La riqueza de especies se concentró al noroeste y sureste de la provincia. La riqueza de endémicos fue localizada en el centro y norte. El análisis de WE mostró tres celdas ubicadas en el centro del área de estudio; el CWE recuperó tres celdas al sur de la provincia. Se reconocen dos grupos principales (subprovincias), anidando grupos más pequeños (distritos). Los distritos corresponden en su mayoría a las ecorregiones del Desierto Chihuahuense, Matorral de la Meseta Central, Bosques secos del Bajío. Conclusiones: Dalea funcionó como subrogado de la flora y reforzó las propuestas de regionalización para esta provincia.

Background: Dalea is endemic to the Americas and has a wide distribution in the Chihuahuan Desert province, its species are associated with xeric scrub, oak forest, and coniferous forest. Hypothesis: Dalea species function as a surrogate of the flora and reinforce the regionalization proposals for this province. Study site and research period: Chihuahuan Desert province, August 2020 to July 2022. Methods: A database was generated from herbarium specimens. The species richness analysis was obtained using a 1 x 1 degrees grid. Weighted endemism (WE) and corrected weighted endemism (CWE) were analyzed and estimated. For regionalization, species replacement was calculated and the UPGMA grouping method was applied. The resulting groups were checked against the published ecoregions to determine the biotic components of the environmental characterization. Results: 3,061 records were obtained, representing 77 species, of which 33 are endemics to the study area. The northwestern and southeastern parts of the province had the highest species richness. The central and northern parts had the highest endemic species richness. The WE analysis showed three cells located in the center of the study area, while the CWE recovered three cells at the south of the province. Two large main subprovinces are recognized, these nesting smaller area groups (districts). The districts mostly correspond to the ecoregions of the Chihuahuan Conclusions: Dalea was a surrogate for the flora and reinforced the regionalization proposals for this province.

Background: Dalea is endemic to the Americas and has a wide in the Chihuahuan Desert province. Its species are associated with xeric scrub, oak forest, and coniferous forest. Hypothesis: Dalea species function as a surrogate of the flora and reinforce the regionalization proposals for this province. Study site and research period: Chihuahuan Desert province, August 2020 to July 2022. Methods: A database was generated from herbarium specimens. The species richness analysis was obtained using a 1 x 1 degrees grid. Weighted endemism (WE) and corrected weighted endemism (CWE) were analyzed and estimated. For regionalization, species replacement was calculated and the UPGMA grouping method was applied. The resulting groups were checked against the published ecoregions to determine the biotic components of the environmental characterization. Results: 3,061 records were obtained, representing 77 species, of which 33 are endemics to the study area. The northwestern and southeastern parts of the province had the highest species richness. The central and northern parts had the highest endemic species richness. The WE analysis showed three cells located in the center of the study area, while the CWE recovered three cells at the south of the province. Two large main subprovinces are recognized, these nesting smaller area groups (districts). The districts mostly correspond to the ecoregions of the Chihuahuan Desert, Scrub of the Central Plateau, and Dry forests of the Bajio. Conclusions: Dalea was a surrogate for the flora and reinforced the regionalization proposals for this province.

The state of Michoacan, Mexico is moderately diverse in Crassulaceae, with 38 species documented to occur there. In this article, two new species of Crassulaceae endemic to the Sierra Madre del Sur of Michoacan are described and illustrated with photos; a new state record is also reported. Echeveria coalcomanensis is known from a single rock outcrop in humid pine-oak forest at 2000 m in the Sierra de Coalcoman. It is placed in series Valvatae based on the inflorescence of cincinni, imbricate bracts, and valvate petals. The species can be easily distinguished from other members of the series by having green, ovate to deltoid leaf blades with a reddish acuminate apex. Sedum larai occurs at two localities separated by 90 km. One is found at the ecotone of oak forest and tropical deciduous forest at 1200 m, the other in pine-oak forest at 2138 m. The new species is similar to two species of Sedum sect. Fruticisedum, S. bourgaei and S. guadalajaranum, from which it differs by being a dwarf, rhizomatous herb with delicate, unbranched stems to 11 cm long. Sedum salazarii was previously known only from western Guerrero and is here reported 200 km to the west in the Michoacan, where it occurs in pine-oak forest and cloud forest at 2300 to 2500 m.

(Loranthaceae) is a neotropical genus currently containing 24 species. Its taxonomic history has included changes in its circumscription and the transfers of some of its species to other genera in the family. Several phylogenetic studies of Loranthaceae have recognized a close relationship between Cladocolea and Struthanthus. However, both genera were poorly represented in these studies, so here we generate a phylogeny of Mexican species of Cladocolea, Struthanthus, and related genera of Psittacanthinae, using nuclear DNA sequences of the ITS region, as well as the chloroplast regions matK and trnL-F. The sample includes 112 new sequences and an additional 12 sequences obtained from GenBank. These represent 23 taxa of Cladocolea, 14 of Struthanthus, and 10 from nine other genera of Loranthaceae. In order to understand character evolution and estimate ancestral states, 13 morphological characters were mapped, both vegetative and reproductive. Bayesian inference and Maximum likelihood analyses were performed using independent matrices and a concatenated matrix of 2842 characters. Our results show that Cladocolea and Struthanthus are both polyphyletic genera. However, the Mexican species of Cladocolea and Struthanthus with convolute or sigmoid styles form a monophyletic group. Finally, the analysis of ancestral character states indicates a trend towards a reduction of inflorescences in the Cladocolea-Struthanthus complex. New combinations and synonymies are proposed.

The most recently described genus of Phytolaccaceae is Nowickea, which was proposed in 1989. It is similar to Phytolacca in most features but distinguished by possessing a well-developed gynophore, larger herbaceous tepals that are frequently elongated, and obovoid to obpyriform fruits with narrowly elliptical seeds. The genus contains two endemic Mexican species that were each long known from a single collection made more than 65 years ago. In 2013, we encountered plants of Nowickea hundreds of kilometers from the previous collections. However, whereas most of the branches had the characteristic features of Nowickea, a few branches had flowers and fruits typical of normal Phytolacca icosandra. It had been suggested that Nowickea may be just a "monstrous " Phytolacca. We concur, and as a result Nowickea is reduced to synonymy under Phytolacca, and the species Nowickea glabra and N. xolocotzii are treated as synonyms of P. icosandra.

Polystemma stevensii, a new species from Michoacán, Mexico, is described and illustrated. It grows in tropical deciduous forest in the Balsas Depression at elevations from 350 to 750 m. Polystemma stevensii is similar to P. viridiflorum but differs by having a gynostegial corona with five lobes fused at the base to form a discontinuous flat ring (vs. not forming a discontinuous flat ring), an internal corona with two deltate lobes (vs. with one ligulate lobe), and globose style head (vs. flat style head). A distribution map of the new species and a key to determine the Polystemma species of Michoacán are provided. Following IUCN Red List guidelines, it is assigned a preliminary category of endangered, EN B1ab(i,ii,iii)+2ab(i,ii,iii). Polystemma now includes eight species, of which five are endemic to Mexico.

Euphorbia is one of the largest genera of flowering plants, and Mexico is one of the primary centers of diversification. Much work remains before a thorough understanding of the Mexican species is reached, and the present contribution aims to unambiguously allow the application of 14 names by clarifying their types. Some of these are distributed outside of Mexico, including Canada, the United States, Central America, South America, and the Antilles. Lectotypes of the following names are designated: E. biformis, E. boliviana, E. elastica, E. gumaroi, E. lancifolia, E. luciismithii, E. macropus, E. mendezii, E. potosina, E. subreniformis, and E. umbellulata. In the absence of original material, neotypes are selected for the following names: E. nudiflora, E. tanquahuete, and E. vermiculata. All the names are currently accepted, except for E. elastica (=E. tanquahuete) and E. biformis (=E. macropus).

Background: The Sierra Madre Oriental is a Physiographic Province located in northeastern Mexico and has distinctive geological, climatic, and edaphic characteristics. The flora in this region has not been inventoried as a whole. Question: What is the floristic diversity of the Physiographic Province of the Sierra Madre Oriental? What is the geographic affinity of its genera? Site and years of study: The Physiographic province of the Sierra Madre Oriental. The work was conducted from August 2012 to December 2020. Methods: An exhaustive search for information was carried out using various sources such as herbaria, databases, floristic works, and monographs. To each species was registered the type of vegetation, geographic affinity and endemism. Results: A total of 6,981 species are registered; 1,542 are endemic to the Sierra Madre Oriental. The most diversity families were Asteraceae (1,000 species), Fabaceae (495), Cactaceae (365) and Poaceae (328). The temperate forests housed the greatest number of species (2,906). Queretaro was the richest state (2,803), followed by Coahuila with (2,710) and Nuevo Leon (2,406). The greatest number of genera of the species in the Sierra Madre Oriental have geographical boreal affinity (2,742), followed by species with tropical affinity (2,020), endemics to Mexico (1,227), with a cosmopolitan distribution (803), and from the deserts of the world (189). Conclusions: The Sierra Madre Oriental is home to more than a quarter of the vascular flora and 13 % of the endemic plants from Mexico. The area combines genera of different geographic affinities, mostly boreal, followed by tropical and endemic.

Euphorbia marciae, a new species from the lowlands of the Balsas Depression in southwestern Mexico, is described and illustrated. The species was first collected by the renowned botanist George B. Hinton during his explorations of the area in the 1930s. It is known from only five collections made in northwestern Guerrero and the extreme southwestern portion of the state of México, at elevations from 250 to 610 m. Vegetation of the area is tropical deciduous forest. Euphorbia marciae belongs to Euphorbia subg. Chamaesyce sect. Anisophyllum and resembles E. apatzingana, E. hyssopifolia, and E. nutans. However, it differs from these species in having smooth seeds. The seeds are nearly identical to those of E. pionosperma, an endemic species occurring in the Sierra Madre Occidental of eastern Sonora and western Chihuahua. However, the leaves of E. pionosperma are more conspicuously serrate and have larger stipules. In addition, Euphorbia pionosperma has smaller involucres and involucral appendages. Following IUCN Redlist criteria, E. marciae should be treated as Data Deficient (DD) until the species can be relocated and its populations field evaluated.

Euphorbi berryi is described and illustrated with photos. It is known from the Cerrado vegetation of Maranhão, Brazil, where it occurs on sandy soils in the municipality of Carolina at elevations of 187 to 350 m. The precise affinities of Euphorbia berryi are not clear, but it undoubtedly belongs to Euphorbia subg. Chamaesyce sect. Anisophyllum. It differs from other species of the section by the combination of being a delicate annual with the stipules united into an erose sheath; slender styles that are notched at the apex; and linear, entire, strongly falcate leaves that are scarcely asymmetrical at the base and have a white, straight to flexuous, quickly deciduous, hairlike extension at the apex. The latter feature is apparently unique in sect. Anisophyllum. Comparisons are made with Euphorbia burchellii and E. potentilloides, two species with which it has been confused. Its conservation status is preliminary assessed to be data deficient (DD) until the populations can be field evaluated.

Background: Polystemma (Apocynaceae subfamily Asclepiadoideae) is a small genus currently with seven species characterized by having white glandular trichomes becoming crystalline in age; filiform corona appendages; and fusiform, smooth, mottled follicles. Exploration in the Balsas Depression of Michoacán, Mexico resulted in the discovery of an unknown species of Polystemma . Questions: Are the unknown Polystemma plants occurring in the Balsas Depression of Michoacán new to science? If so, how are they distinguished from other species of the genus, what are their ecological preferences, what is their distribution, and are they endangered? Studied species: Species of Polystemma . Study site and dates: Balsas Depression, Michoacán, México; 2001, 2003, 2004, 2014. Methods: Fieldwork to collect herbarium specimens and photograph plants; review of literature on Polystemma to determine taxonomic status; preparation of a morphological description; evaluation of conservation status using IUCN Redlist criteria. Results: Polystemma fishbeiniana is proposed as a new species and illustrated with photographs. It occurs at two locations in the xeric scrub and open thorn forest of the Zicuirán-Infiernillo Biosphere Reserve, at elevations from 275 to 400 m. Flowering occurs from June to September, with mature fruits present from October to March; dehisced fruits can persist on the plants for almost a year. Its conservation status is assessed as Endangered, EN B1ab(iii)+2ab(iii). Conclusions: Polystemma fishbeiniana is distinguished from congeners by its suffrutescent habit, small leaves, and flowers abaxially yellowish with a blackish to dark burgundy red margin and central line with short lateral extensions.These traits are otherwise unknown in the genus. Translate stop Translate stop

Acalypha (Euphorbiaceae: Acalyphoideae) is a large, monophyletic genus distributed worldwide in tropical and subtropical regions, with a few species extending into temperate areas of southern Africa, Asia, and North and South America. We reconstructed phylogenetic relationships within the genus using DNA sequences from the plastid ndhF and trnL-F regions and the nuclear ribosomal ITS region, sampling 142 species to represent the geographic, morphologic, and taxonomic diversity with the genus, resulting in a 162 (158 in Acalypha) terminal and 3847 character combined dataset. Bayesian and maximum likelihood reconstructions based on the combined dataset yielded a tree with a generally well-supported backbone and several strongly supported clades. Our results strongly supported the monophyly of Acalypha subg. Acalypha as currently recognized but showed that A. subg. Linostachys and almost all other infrageneric taxa recognized in the most recent comprehensive classification of the genus were not monophyletic. We therefore propose a new subgeneric classification comprising A. subg. Acalypha, A. subg. Androcephala, A. subg. Hypandrae, and A. subg. Linostachys (s.s.). Our results also shed light on relationships within some species groups, including in what has been treated as a broadly defined A. amentacea, in which we recognize A. amentacea, A. palauensis comb. nov., and A. wilkesiana as distinct species. Bayesian ancestral state estimations based on the phylogeny of Acalypha demonstrated that inflorescence position and sexuality and habit show high homoplasy, especially within A. subg. Acalypha, and that inflorescence position and habit exhibit correlated evolution.

Serjania is among the largest Neotropical genera of Sapindaceae and comprises ∼240 species. Traditionally, the genus has been defined by its schizocarpic fruits separating into three distally winged mericarps. However, recent phylogenetic studies have revealed that fruit type is not consistent within the genus and that it also includes a few species having capsular fruits that were previously placed in other genera. A phylogenetic analysis is presented based on nuclear ITS and chloroplast trnL-F sequences. The ingroup consisted of 48 species broadly sampled from across the geographic range and taxonomic spectrum of Serjania and focusing on species with atypical fruits. An ancestral character state reconstruction of fruit type was performed and demonstrated that the ancestral fruit type of the genus is strongly supported to be a schizocarp, but there are at least five independent derivations to capsular fruits and at least one transition back from capsules to schizocarps. Also, transitions from winged to wingless mericarps have occurred at least twice. Infrageneric classification is problematic and all of the sections that were represented by more than one species come out as poly- or paraphyletic. Our limited sample of taxa precludes the possibility of a new classification at present and a broader phylogenetic sample of the genus will be needed to understand relationships and determine which lineages warrant formal recognition. In addition to the phylogenetic study, Serjania frutescens, a new capsular-fruited species from Michoacán, Mexico, is described, illustrated, and compared with its putative closest relatives. A key is provided to differentiate this species from other Mexican Serjania with capsular fruits, and new synonymies and lectotypifications associated with capsular-fruited Serjania tortuosa and S. sonorensis are established. Phylogenetic results suggest that these two are cryptic species and at least superficially indistinguishable by morphology.