In a comparative ecophysiological study of two fern species (Athyrium filix-femina and Anisocampium niponicum) growing in the same microenvironmental patch among other ferns on a north facing slope in Palisades, N. Y., the two species had similar maximum photosynthesis rates (3.6 and 3.1 µmol m^–2 s^–1, respectively), but the light intensity (PPFD) required to reach saturation was somewhat higher for A. niponicum compared to A. filix-femina. The dark respiration rate was higher for samples from A. niponicum (0.54 µmol m^–2 s^–1) compared to A. filix-femina (0.40 µmol m^–2 s^–1). Leaf stomatal density expressed as number cm^–2 was higher in A. niponicum (4,538) compared to A. filix-femina (2,660), although stomatal size in the two species was fairly similar (c. 48 – 54 µm length and 28 – 30 µm width). The chlorophyll content index (CCI) for A. niponicum was higher (4.72) than A. filix-femina (2.99). Based on leaf fluorescence analysis, Ψ_o (efficiency with which a trapped exciton can move an electron into the electron transport chain) was higher in A. niponicum (0.73) than A. filix-femina (0.66). The significance of this remains to be determined, but may indicate that higher chlorophyll concentrations correlate to a greater stability of the elevated energy electron (exciton) in PS2 reaction centers due to electron quantum resonance coherence among the light harvesting molecules, and a resulting increased probability that the electron will pass on to the intermediate quinone and beyond in the electron-transport chain.

Studies on fern gametophytes are lacking in comparison to their sporophyte counterparts, yet they are equally important to our understanding of fern ecology and evolution. Only one study has previously described the gametophytes of Microgramma. The goal of our study was to observe and document spore morphology and early developmental stages of the gametophytes of the fern, Microgramma brunei. Gametophyte development, morphological characters, and reproductive behavior were observed over the course of two months. A derivative of the classic “Farrar Type 1” cordiform gametophyte morphology was documented for M. brunei and a weak antheridiogen system was identified. This study is the first to focus on the gametophytes of a myrmecophytic species of Microgramma. These findings offer new insight into the biology of Microgramma brunei, a unique species of tropical fern.

Plant phenology describes the response of plants to cyclic environmental fluctuations and is a powerful tool in the face of climate change. Most phenological studies in ferns have focused on humid environments, where water is not a limiting factor. However, Mexico has a great diversity of ferns growing in xeric environments (ca. 120 species). We studied the preference for slope aspects and phenological patterns of four of these desiccation-tolerant fern species in a seasonally dry shrubland of central Mexico for 18 months. South-facing rock surfaces and rock tops reached up to 6°C higher air temperatures and up to 24°C higher rock temperatures than North-facing rock surfaces. Myriopteris aurea grew most frequently on the hot rock tops, whereas M. myriophylla and Gaga kaulfussii were most common on cooler northern aspects, and Pellaea ternifolia was found on all lateral rock surfaces. Leaf production and growth of all species were positively correlated with rainfall, but the total leaf number was not seasonal because of their desiccation tolerance. Myriopteris aurea was the first to develop new leaves after the first rainfalls but its leaves dehydrated faster than in the other three species. Myriopteris myriophylla had scaly leaves with the longest life span (7.9 ± 1.1 months), whereas G. kaulfussii had the fastest rehydrating leaves and the highest leaf production during the rainy season. Pellaea ternifolia had glabrous leaves with the shortest life span (4.8 ± 0.2 months). We conclude that each fern species developed a different combination of xeric adaptations to survive under these extreme environmental conditions.

The phylogenetic position of the Greater Antillean genus Atalopteris in the Dryopteridaceae was evaluated on the basis of three chloroplast markers (rbcL, atpA, and trnL-F) from tissue samples of two specimens of the Cuban species A. aspidioides. The results show that Atalopteris is nested in Ctenitis; however, the current taxon sampling is insufficient to determine which species of Ctenitis are most closely related to it. A replacement name, for A. aspidioides (Ctenitis cubensis) is provided.

Ex situ conservation is an essential tool for combatting biodiversity loss. The Fern Lab at the National Botanical Garden in Kaua‘i was established with the goal of propagating some of the world’s most imperiled plants, including 22 Hawaiian species that are considered endangered or critically endangered by IUCN. We provide basic protocols for fern propagation and maintenance with an emphasis on sterile technique. We describe the facility design, tools and materials needed, a step-by-step guide for sterilizing media, and protocols for maintaining healthy cultures from spore to sporophyte. Because the NTBG Fern Lab handles a large number of threatened and endangered species, special care is taken to avoid contamination; however, the techniques presented here could be employed or adapted by professionals or hobbyists alike.