The cataloging of the vascular plants of the Americas has a centuries-long history, but it is only in recent decades that an overview of the entire flora has become possible.We present an integrated assessment of all known native species of vascular plants in the Americas. Twelve regional and national checklists, prepared over the past 25 years and including two large ongoing flora projects, were merged into a single list. Our publicly searchable checklist includes 124,993 species, 6227 genera, and 355 families, which correspond to 33% of the 383,671 vascular plant species known worldwide. In the past 25 years, the rate at which new species descriptions are added has averaged 744 annually for the Americas, and we can expect the total to reach about 150,000

Globally, a majority of people use plants as a primary source of healthcare and introduced plants are increasingly discussed as medicine. Protecting this resource for human health depends upon understanding which plants are used and how use patterns will change over time. The increasing use of introduced plants in local pharmacopoeia has been explained by their greater abundance or accessibility (availability hypothesis), their ability to cure medical conditions that are not treated by native plants (diversification hypothesis), or as a result of the introduced plants' having many different simultaneous roles (versatility ypothesis). In order to describe the role of introduced plants in Ecuador, and to test these three hypotheses, we asked if introduced plants are over-represented in the Ecuadorian pharmacopoeia, and if their use as medicine is best explained by the introduced plants' greater availability, different therapeutic applications, or greater number of use categories. Drawing on 44,585 plant-use entries, and the checklist of >17,000 species found in Ecuador, we used multi-model inference to test if more introduced plants are used as medicines in Ecuador than expected by chance, and examine the support for each of the three hypotheses above. We find nuanced support for all hypotheses. More introduced plants are utilized than would be expected by chance, which can be explained by geographic distribution, their strong association with cultivation, diversification (except with regard to introduced diseases), and therapeutic versatility, but not versatility of use categories. Introduced plants make a disproportionately high contribution to plant medicine in Ecuador.

The pollen record from Lagunas de Mojanda, located at 3748 m a.s.l. (northern Ecuadorian Andes) reflects the vegetation and climate dynamics for the last ca 3400 cal yr BP. Paramo vegetation has been the main vegetation type since the beginning of the record. At Lagunas de Mojanda, from the last ca 3400 to 2200 cal yr BP, grass paramo was well represented mainly by Poaceae (40%) and the occurrence of Valeriana (5%), while montane forest taxa were poorly represented and sub paramo taxa were rare. The vegetation composition suggests cool and humid conditions. Between ca 2200 and ca 1300 cal yr BP, montane rainforest and sub paramo taxa had a higher presence but paramo taxa remained the main vegetation type in the study area, suggesting cool climatic conditions. From ca 1300 to ca 500 cal yr BP, paramo vegetation remained stable, with higher presence of Phlegmariurus and Isoetes, suggesting cool and humid conditions. The last ca 500 cal yr BP generally show lower frequency of montane rainforest and sub paramo taxa. Páramo vegetation reached the highest share, with the presence of Poaceae, Plantago and Ranunculus suggesting a trend of peat bog drying. Fires were present during the whole record, perhaps human-caused, but the study area does not show great disturbance except from ca 1300 to 500 cal yr BP, a period of an evident higher influx of charcoal particles coincidentally with nearby ancient human occupation.

Forests dominated by Polylepis pauta occur in humid environments in the high Andes of Ecuador, Peru and Bolivia, at elevations between 3500–4500 m. Polylepis forests host a unique biodiversity of plants and animals and are an important supply of resources for local people. However, these forests are being destroyed by extensive burning practices, causing the replacement of the forest by grassland and favoring cattle grazing. As a consequence, Polylepis forests have become severely diminished and fragmented, and are considered as one of the most threatened ecosystems in South America. The vascular flora of Ecuadorian P. pauta forests has been documented in detail but little is known about bryophytes of these forests. This paper deals with the liverwort flora of remnant P. pauta forests in the páramo of Papallacta near Quito, Ecuador. The forest floor and trunk bases were almost completely covered by Lepidozia auriculata and four robust Plagiochila species (P. dependula, P. ensiformis, P. fuscolutea, P. ovata). Frullania paradoxa, Leptoscyphus hexagonus, Plagiochila bifaria and P. punctata were abundant on branches of Polylepis trees. In total 51 liverworts were recorded, being the highest number of liverwort species reported from Polylepis forest. Leptoscyphus leoniae Gradst. and Plagiochila pautaphila Gradst. & León-Yánez are new to science.

It remains poorly understood how the composition of leaf wax n -alkanes reflects the local environment. This knowledge gap inhibits the interpretation of plant responses to the environment at the community level and, by extension, inhibits the applicability of n - alkane patterns as a proxy for past environments. Here, we studied the n - alkane patterns of five Miconia species and one Guarea species , in the Ecuadorian Andes (653–3,507 m a.s.l.). We tested for species - specific responses in the average chain length (ACL), the C /(C + C ) ratio (ratio), and individual odd n - alkane chain lengths across an altitudinally driven environmental gradient (mean annual temperature, mean annual relative air humidity, and mean annual precipitation). We found significant correlations between the environmental gradients and species - specific ACL and ratio, but with varying magnitude and direction. We found that the n - alkane patterns are species - specific at the individual chain length level, which could explain the high variance in metrics like ACL and ratio. Although we find species - specific sensitivity and responses in leaf n -alkanes, we also find a general decrease in “shorter” (C ) chain lengths with the environmental gradients, most strongly with temperature, suggesting n -alkanes are useful for reconstructing past environments.