Nucleotide sequences encompassing the chloroplast rps4 gene and the rps4-trnS intergenic spacer were obtained for several specimens representing North American and Hawaiian members of Pteridium aquilinum (ingroup), as well as Pteridium esculentum (outgroup). Nucleotide divergence between ingroup bracken taxa was low. The rps4-trnS intergenic spacer contained indels distinguishing P. aquilinum and P. esculentum. Phylogenetic analyses and a haplotype network recognized two major groups within Northern American bracken that are divided along both genetic and geographic lines. The Hawaiian var. decompositum and the western North American var. pubescens share a similar chloroplast genome and grouped together. Despite morphology and geographical distribution, sequences for var. feei and eastern North American var. latiusculum were very similar and grouped together. Sequence data could not distinguish eastern North American var. latiusculum and the southeastern North American var. pseudocaudatum. Haplotype and biogeographic analyses suggest a most recent common eastern North American ancestor for the ingroup.

Most studies of spore germination in seedless vascular plants have involved species that develop surficial, photosynthetic gametophytes following spore germination. However, several species, including Lycopodium clavatum, give rise to subterranean, nonphotosynthetic, mycorrhizal gametophytes and their spores germinate in the dark. Red light, like white light, inhibits the germination of these spores. Germination occurs after exposure to far-red light. The effects of far-red light are reversed by red light and those of red light are reversed by far-red light confirming the involvement of phytochrome. The active form of phytochrome, Pfr, inhibits germination in L. clavatum. It appears that this is a general phenomenon in seedless vascular plants with subterranean, mycorrhizal gametophytes because it is now known to occur in two species, L. clavatum and Ophioglossum crotalophoroides, from unrelated families. The photoinhibition of germination by white or red light insures that these spores germinate underground in nature providing improved chances of spores obtaining adequate soil moisture and mycorrhizal colonization of young gametophytes that are essential for continued development.

Thelypteris soridepressa, known only from the type collection, is described and illustrated. The species belongs to subg. Amauropelta sect. Apelta A.R. Sm. It is superficially similar to Thelypteris micula from Peru in its small, very thin-textured leaves and short trichomes on the adaxial surface of the veins, but can be distinguished by the lack of resinous dots and indusia, as well as by its sunken sori. It has no close relatives in Brazil.

Cheilanthes pantanalensis, a new species from the Brazilian Pantanal is described. A complete morphological description is presented, as well as illustrations and comments on the most similar species. This species is distinguished by its (2-)3-pinnate leaves and by having ultimate segments that are ovate to suborbicular. We also report Cheilanthes hassleri and C. obducta as new records for Brazil, both from Mato Grosso do Sul.

A new species of grammitid fern, Melpomene anazalea Sundue & Lehnert from Colombia, is described and illustrated. It stands out in the genus for its particularly small size and abundantly setose lamina. It is known from protected rock crevices in relatively dry páramos.

Based on extensive studies of grammitid ferns (Polypodiaceae) in the field and as specimens in various herbaria, eleven new species in the genus Melpomene are recognized from the Neotropics: Melpomene albicans, M. caput-gorgonis, M. flagellata, M. huancabambensis, M. jimenezii, M. michaelis, M. occidentalis, M. paradoxa, M. personata, M. sklenarii, and M. vulcanica. All are restricted to the Andes except for M. personata, which also extends to Mesoamerica and the Caribbean. The morphology and distribution of all species are illustrated.