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).

Herbarium specimens of wild Mexican Leguminosae with ethnobotanical information are an important resource for understanding human–legume interactions. The 525 useful legume species registered in Mexico’s National Herbarium (MEXU) were analyzed using a hierarchical method and represented in dendrograms. Of these, 244 species noted a single use, while 281 species reported two or more uses. Plants applied for medicinal purposes registered the greatest number of species (351 spp.), followed by those employed as animal food (205 spp.), material sources (197 spp.), environmental modifiers (139 spp.), and food and food additives (119 spp.). This study also suggests that a greater number of uses is concentrated in closely related species-rich taxa rather than in less diverse groups, and that certain uses are clustered in phylogenetically related groups. Of particular interest are multipurpose shrubs and trees managed as living fences that satisfy a variety of needs in rural areas. This diversity of legume resources used by Mexican people may be advantageous in the planning and management of conservation areas, since the diversity, ubiquity, and economic importance of some of species have promoted overuse and destruction.

Astragalus is the most diverse genus within flowering plants with almost 2500 species, it is widely distributed around the world, very abundant in temperate regions of the Northern Hemisphere, in central and western Asia, Turkey, Iran, and Afghanistan, central Asia, Europe, Mongolia, Siberia, northeastern China, and Japan. In the American continent it is especially abundant in Canada, western United States, Mexico, and South America. Given the diversity of Astragalus species present in Mexico, the recent description of at least 15 new species for this country, the absence of a recent study that encompasses all the new findings and that the last general study for Mexico dates back almost 60 years, we consider necessary a new taxonomic synopsis that encompasses all the new information, which is presented here. The study records 102 species of Astragalus in Mexico. This work is based essentially on the review of collections of specimen samples, type specimens in national and foreign herbaria, data bases, and the collection of specimens of this genus by the authors in the last 40 years and that covers practically the entire area where this genus is distributed in Mexico. In this study we recorded 102 species and 46 infraspecific taxa; seventy one species and 17 varieties are endemic to Mexico. Baja California (32), Chihuahua (25), Durango (23), Sonora (22), Coahuila (20), San Luis Potosí (17), Nuevo León (17), and Zacatecas (15) are the states with the greatest species richness. In Mexico, the diversity of Astragalus species decreases from north to south and from west to east. Most of the species of Astragalus in Mexico are distributed in the mountains, followed by low and arid plains, including coastal dunes, those last ones, exclusively of the northwestern region. There are no records of any Astragalus species in Campeche, Tabasco, Quintana Roo or Yucatan. The dichotomous keys are based mainly on the color of flowers, the shape of the pod and if the fruit is sessile or stipitate. For each species is included also a morphological description, habitat, altitudinal range, and distribution map.

Desmodium diversity has been mainly classified using fruit characters, and because of variability in these and other characters, the taxonomy has sometimes been problematic and thus, there is a need for clarification and taxonomic reassessments. This is the case for the Desmodium procumbens group, where several infraspecific taxa have been named. The phylogenetic relationships among taxa referred to this group is unknown, and the taxonomic status has been recently revised only for some of the taxa. In this study, pollen morphology and ultrastructure of D. neomexicanum, D. procumbens var. procumbens, D. procumbens var. exiguum, D. procumbens var. longipes and D. procumbens var. transversum, belonging to the Mexican Desmodium procumbens group, were examined using light, phase-contrast, scanning electron and transmission electron microscopy, in order to establish palynological characters that might contribute to a better taxonomic resolution. Pollen grains are tricolporate, radiosymmetric, oblate spheroidal to prolate spheroidal shape, with lalongate endoapertures and rugulate exine with foveolae between rugulae. The exine is tectate with a columellate and/or granulate structure. The absence of a fastigium, features of exine sculpture, a colpus membrane and infrastructure mainly dominated by granules differentiate the pollen grains of the varieties exiguum and transversum from the other taxa studied. Pollen traits and sequence data provide evidence for separating D. neomexicanum from species D. procumbens. In general, the result from the pollen analysis is congruent with results obtained from a preliminary molecular analysis of this group.