We describe Anemia paripinnata, a new species from the rock outcrops of Central Brazil. It is remarkably distinct from most of its congeners by having paripinnate lamina, a character that is only found in the Amazonian A. dardanoi. The new species is described, illustrated, and compared to the most similar species in the genus. The new species is known from few collections in Mato Grosso. Based on the IUCN criteria, it can be considered an endangered species.

The origin of ×Lindsaeosoria flynnii as an intergeneric hybrid between Lindsaea ensifolia and Odontosoria chinensis is here confirmed by molecular analysis of plastid data and Illumina high-throughput sequencing of the low-copy nuclear LEAFY gene. Plastid DNA grouped the hybrid together with Lindsaea ensifolia, suggesting that it is the maternal progenitor, while the presence of distinct LEAFY alleles confirmed the hybrid origin. Together with ×Cystocarpium this is confirmed example of deep hybridization event between fern lineages that were separated in the early Cenozoic or late Mesozoic.

The most abundant fern species in northeast United States forests are wintergreen. These ferns keep their fronds for one year before replacing them in the spring. The wintergreen fronds soften at their base in fall and survive the winter under snow, allowing vernal photosynthesis and providing an energetic benefit to the plant. This study addressed whether or not the softening of the stipe is critical to the evolutionary adaptiveness of the wintergreen leaf habit. I kept the fronds of 12 Dryopteris intermedia plants upright through the winter of 2015–2016 and left those of 12 other plants prostrate as controls. In the spring of 2016, a greater proportion of the frond surface area had frost damage on the upright fronds than on the control plants, and a greater proportion of the fronds were broken in the upright plants than in the control plants. The softening of the stipe was probably a critical step in the evolution of the wintergreen habit in D. intermedia.

Pityrogramma hirsuta Testo is described from a secondary lowland rain forest on the Osa Peninsula of Costa Rica. It is distinguished from all other Costa Rican Pityrogramma species by a combination of once-pinnate-pinnatifid laminae, abundant whitish hairs on the petiole, rachis, and laminar surface, and complete lack of farina on the abaxial laminar surface. A hybrid between this species and Pityrogramma calomelanos (L.) Link, Pityrogramma ×watkinsii Testo is also described. It is morphologically intermediate to its progenitors and is characterized by an indument of whitish hairs on the petiole, rachis, and laminar surface, and sparse white farina on the abaxial surface of the lamina. The new species and hybrid are each known only from the type collections. Relationships to other species of Pityrogramma are discussed, and a key to Central American Pityrogramma is presented.