Four members of the alpha-tubulin gene family were examined in Ceratopteris richardii. Genetic linkage mapping based on a population of nearly 500 Doubled Haploid Lines was able to position three or four members of this gene family on linkage groups 17, 24, and 28, respectively (two of the four observed polymorphic restriction fragments containing alpha-tubulin genes are either identical or map too close to each other on linkage group 17 to be distinguishable in map distance). Non-mapable monomorphic bands observed on probed Southern blots suggest that the alpha-tubulin gene family in this species is large. Four alpha-tubulin genes from C. richardii were sequenced and found to be fairly similar to each other in terms of their amino acid sequences, with their greatest diversity at the carboxy-terminal ends. BLAST comparisons found each of these four amino acid sequences more similar to an alpha-tubulin from a dicot, gymnosperm, or alga species than it was to any other alpha-tubulin sequence presently known from Ceratopteris or from the fern Anemia phyllitidis or the moss Physcomitrella patens. Bayesian phylogenetic analysis of nucleotide sequences placed three of the four Ceratopteris alpha-tubulin gene copies in a clade with copies from Pseudotsuga and Anemia, consistent with a history of two gene duplication events, one following and one preceding the divergence of ferns and seed plants. The fourth copy is robustly separated from the preceding three and placed in a clade of algal alpha-tubulin genes, suggesting its divergence from the ancestor of the other three before the divergence of algae and land plants. As characterized thus far, the alpha-tubulin gene family of C. richardii is relatively large as compared to the six copies known from fully sequenced Arabidopsis thaliana, a condition that may be correlated with the large genome size and diverse life history constraints of this homosporous fern species. These findings suggest several new opportunities for research into the evolution, function, and regulation of the alpha-tubulin gene family in Ceratopteris.

We describe ten new species of Blechnum (Blechnaceae, Pteridophyta) from Bolivia and provide a key to the Bolivian species of the genus. The new species are: B. bicolor, B. bolivianum, B. bruneum, B. cochabambense, B. pazense, B. reflexum, B. repens, B. smilodon, B. squamatum, and B. vallegrandense. Blechnum gracilipes and B. squamipes are elevated to species rank.

The purpose of this study was to investigate the nutritional status of Pteridium caudatum (bracken fern) in a Neotropical region where this species occurs in acid leached soils. In this region there is a high availability of Al in soluble toxic forms, rendering P. caudatum an important weed associated with wildfire regimes. Water-soluble Ca, exchangeable Ca fraction, Ca bound to pectate phosphate, and bound to oxalate were evaluated from P. caudatum sampled from a burned parcel of land 94 and 270 days after an accidental fire, as well as from an unburned control parcel. Both sites were located in a tropical secondary savanna community in a successional mosaic of a cloud forest. The concentrations of total Ca, N, P, K, Mg, Fe, Mn, Zn, Cu, Ni and Al, and their distribution in the plant organs were investigated. The study addressed the hypothesis that shoots should show low concentrations of Ca because a low cation capacity exchange has been reported in roots of Pteridium. We expected a low water-soluble Ca fraction because bracken has been defined in the literature as a non-calcicole plant. The exchangeable fraction and pectate phosphate bound Ca constituted 60 to 85% of the total Ca in pinnae and rhizomes, while the oxalate bound Ca constituted only 3 to 14% of the total Ca. Concentrations of Al as high as 248.3 mmol kg⁻¹ were found in roots. Pinnae showed only 84.53 mmol Ca kg⁻¹ and 5.62 mmol Al kg⁻¹, and their Ca/Al ratio was 15 mol mol⁻¹ contrasting with P. aquilinum from temperate regions where Ca/Al was 1440 mol mol⁻¹, however the Ca/P was 2 mol mol⁻¹ in both species. We conclude that P. caudatum behaves as a potassium plant (soluble K/Ca >>1) such as the grass-like families Poaceae and Cyperaceae and accumulates Al in the subterranean organs.

We have sequenced the complete plastid genome of the fern Angiopteris evecta. This taxon belongs to a major lineage (marattioid ferns) that, in most recent phylogenetic analyses, emerges near the base of the monilophytes. We used fluorescence activated cell sorting (FACS) to isolate organelles, rolling circle amplification (RCA) to amplify the plastid genome, followed by shotgun sequencing to 8X depth coverage, and then we assembled these reads to obtain the plastid genome sequence. The circular genome map has 153,901 bp, containing inverted repeats of 21,053 bp each, a large single-copy region of 89,709 bp, and a small single-copy region of 22,086 bp. Gene order is similar to that of Psilotum. Several unique characters are observed in the Angiopteris plastid genome, such as repeat structure in a pseudogene. We make structural comparisons to Psilotum and Adiantum plastid genomes. However, the overall structural similarity to Psilotum indicates either wholesale conservation of genome organization, or (less likely) repeated convergence to a stable structure. The results are discussed in relation to a growing comparative database of genomic and morphological characters across the green plants.

Pleopeltis orientalis and P. oreophila are described as new. Pleopeltis orientalis is restricted to the Cordillera Oriental of Colombia. It resembles the South American species Pleopeltis fraseri (Mett. ex Kuhn) A. R. Sm. and Pleopeltis remota (Desv.) A. R. Sm. Pleopeltis oreophila is found in interandean valleys of northern Peru. It resembles Pleopeltis pycnocarpa (C. Chr.) A. R. Sm. and Polypodium segregatum Hook.

Based on herbarium specimens and recent collections made in the last few years, we have found 19 species that are for the first time recorded for Bolivia (9 species) and/or Brazil (12 species). Full specimen citations, comments about previously known distributions, and taxonomic notes are presented for all species. In Bolivia, all new records are for species of Adiantum, mostly from lowland regions in northern and eastern Bolivia. In Brazil, most of the new records are for Amazonian Brazil, near the boundaries with neighboring countries. One record is for southern Bahia, showing a clear disjunction between Venezuelan-Guayanan Shield and the Serra do Mar Mountains in northeastern Brazil.