Salvinia minima is a relatively small, floating aquatic leptosporangiate fern in the family Salviniaceae. It is widely distributed in the horticultural trade as an ornamental plant for aquaria and aquatic gardens. Consequently, it has escaped into the natural environment where it produces large, dense mats of branching ramets that are often deleterious to other aquatic biota, particularly in tropical and mild temperate regions. This is a report of a laboratory experimental study of the growth, photosynthesis and dark respiration of S. minima, particularly addressing the variables in a way that is potentially relevant for environmental and ecological research applications. Photosynthetic carbon assimilation rates are inversely related to the leaf area of the ramets, and approximates a second-order polynomial function defined by non-linear regression analysis (p < 0.01); namely, A = 6.3761 - 0.3381 _* L + 0.005 _* L², where A is CO₂ assimilation rate (µmol m^–2 s^–1) and L is leaf area of the ramets (cm²). Data are also presented on the quantum yield efficiency (F_v/F_m) and electron transfer (ET₀/RC) for ramet leaves of different sizes, indicating that low quantum yield efficiency most likely accounts for lower CO₂ assimilation rates in more mature ramets with larger leaves. The dark respiration is approximately equivalent to 30% of the net photosynthesis CO₂ assimilation rate. The relative growth rate (RGR) is 0.03 accounting for about a 4% gain in weight per day relative to the initial weight of the S. minima ramets.

In this paper, we present the lectotypification of 57 names of ferns and lycophytes for a total of 60 taxa studied. These names belong to species that occur mainly in the Guianas and other localities in the Neotropical region. Most of these names (46) are synonyms and others (14) are names in use. Among these 57 lectotypifications, 45 are here designated, 10 of them were already made by previous authors, but were overlooked by subsequent authors or for which we give additional information, and two others are second-step lectotypifications (Adiantum tomentosum and Pteris biformis). Two holotypes have been confirmed, and for one name (Adiantum petiolatum), typification was not possible to make because we did not find the original material. For all cited types, we provide information about the presence of barcode or accession numbers. This information allows easy localization of the type specimens and their image through the Word Wide Web.

Anthropogenic climate change is projected to have an especially negative impact on the survival of plants that are dependent on limited microclimatic refugia or that already reside at their climatic extreme. Gymnocarpium appalachianum is a narrowly endemic fern restricted to cold mountaintops and algific vents in the central and southern Appalachian region of eastern North America. It is the much rarer of the two documented diploid parents of the circumboreal allotetraploid G. dryopteris––one of the most widespread fern species on the planet. Gymnocarpium appalachianum is a good case study for forecasting how evolutionarily significant, but rare, species might survive on a warming planet. We utilize an ecological niche modeling approach (MaxEnt) to explore the projected distribution of G. appalachianum under past (Last Glacial Maximum) and future climate models. All known verified herbarium records of G. appalachianum were georeferenced, for a total of 70 occurrence points. Nineteen standard bioclimatic variables extracted from WorldClim were used to model near-current climate projections; representative concentration pathways (RCPs 2.6 and 8.5) were used for future climate projections (2070). The temperature annual range, mean temperature of warmest quarter, precipitation of driest month, precipitation of coldest quarter, and mean diurnal range were identified as the key variables for shaping the distribution of G. appalachianum. An unanticipated result from our analyses is that G. appalachianum has past and current projected habitat suitability in Alaska. Because this overlaps with the current range of G. disjunctum, the other diploid parent of G. dryopteris, it suggests a possible region of origin for this circumboreal tetraploid descendent of G. appalachianum––a research avenue to be pursued in the future. Our study envisions a dire fate for G. appalachianum; its survival will likely require an urgent contingency plan that includes human-mediated population relocation to cooler, northern locations. Understanding the long-term sustainability of narrowly endemic plants such as G. appalachianum is critical in decisions about their management and conservation.

We describe Elaphoglossum auralolitae, a new species from southwestern Guatemala. The new species belongs to the Elaphoglossum petiolatum complex, in Elaphoglossum section Lepidoglossa, one of the largest sections within the genus. Elaphoglossum auralolitae is characterized by petioles and laminae densely scaly, with large scales including those of costae and margins; the presence of resinous dots on the petioles (mostly obscured by the scales) and on the abaxial laminar surface; and spores with spiny perispores. Only a dozen collections are known of this species so far, all of them from the Sierra Madre mountains in southwestern Guatemala. The first collection of this species was made in 1938 and the most recent was in 1992. We provide a description, taxonomic comments, geographic distribution, phenology, and illustrations for this new species.

Describimos Elaphoglossum auralolitae, una especie nueva del suroeste de Guatemala. Esta especie forma parte del complejo de Elaphoglossum petiolatum, el cual hace parte de Elaphoglossum sección Lepidoglossa, una de las secciones más grandes dentro del género. Elaphoglossum auralolitae se caracteriza por pecíolos y láminas densamente escamosos, con escamas grandes, incluyendo las de la costa y las márgenes; presencia de puntos resinosos en los pecíolos (generalmente cubiertos por las escamas) y en la superficie laminar abaxial, y esporas con perisporas espinosas. Hasta el momento se conocen únicamente una docena de colecciones de esta especie, todas provenientes de la Sierra Madre en Guatemala. La primera colecta se realizó en 1938 y la más reciente en 1992. Este trabajo incluye la descripción e ilustración de esta nueva especie, imágenes de sus esporas, comentarios taxonómicos, distribución geográfica y fenología.