A new record of the fern genus Cornopteris Nakai from Peninsular Malaysia is presented. The species, C. opaca (D. Don) Tagawa was encountered during recent fieldwork in Mount Berinchang, Cameron Highlands. Previously, it has only been recorded from Mount Kinabalu in Sabah, East Malaysia. A description, photographs, and a distribution map of known occurences in Malaysia have been provided.

We describe Serpocaulon psychotrium, a new species from northern South America, and provide for it a discussion of similar species, line drawings, field photographs, and a distribution map. It is often confused with, and probably related to, the species commonly called S. caceresii, also widespread in South America. We reinterpret S. caceresii as a heterotypic synonym of S. articulatum, an older name, and review the nomenclature of that species. Also, we provide a list of representative specimens for both species and a key to all pinnate species of Serpocaulon.

Understanding features that fostered the persistence of Equisetum–Earth's oldest extant vascular plant genus–since Mesozoic times and through episodes of significant global environmental change, is of current interest in view of modern challenges to plant survival. In addition to known structural and physiological adaptations, we hypothesized that microscopy and shotgun metagenomic sequencing might reveal eukaryotic microorganisms such as fungi that may aid Equisetum survival. Here, we report evidence for several lineages of eukaryotic microbes associated with giant Equisetum xylochaetum, which dominates vegetation in saline streambeds of remote valleys in the hyper-arid Atacama Desert, Chile. Plant material was collected and field-preserved at two comparatively low-disturbance sites; DNA extracted in Chile using low-shear methods was later sequenced, 18S and 28S rDNA taxonomic marker sequences were selected for SILVAngs classification, allowing comparisons to eukaryotic microorganisms previously inferred for earlier-diverging plant lineages. SEM, fluorescence microscopy, and/or LM of toluidine blue-stained sections of roots indicated protists, epiphytic and endophytic fungi, and cortical nematodes. Eukaryotic genera inferred from 18S rDNA at >100X mean sequencing depth included the ciliate Engelmanniella, hyphal chytrid Monoblepharella, predatory ascomycete Cephaliophora, a salpingoecid choanoflagellate, and an annelid worm. 23S rDNA sequences indicated ascomycete Capnodiales fungi at one site and four types of Pezizomycotina fungi at the other. No evidence for vesicular-arbuscular mycorrhizal fungi was found, but we hypothesized that Equisetum may benefit from other types of fungal associations, some possibly inherited from ancestral plant lineages.

Wintergreen ferns keep their leaves for an entire year before replacing them with new leaves in the spring. The overwintering leaves of Dryopteris intermedia provide carbon to the new leaves, and if these old leaves cannot become prostrate before winter via the hinge that develops at the base of the petiole, they are frost damaged and broken, which may affect the development of the new leaves in the subsequent year. I compared the vernal development of new leaves in D. intermedia between plants whose old leaves were intact and those whose petioles had been experimentally broken in the fall to determine the importance of the softening of the petiole-base in old leaves to the development of new leaves. Compared to the control, plants whose old leaves had broken petioles had a one-week delay in the development of their new leaves. This delay demonstrates that the evolutionary development of the petiole hinge may have been critical to the functional benefit associated with new leaf development in the wintergreen leaf habit in ferns.

Ferns are the second most diverse group of higher plants on the planet. However, the metabolic processes of these plants, as well as their reaction to the influence of various environmental factors, benefit from new investigation. In seed plants, an important role of the lipid fatty acid (FA) composition in plant response to a variety of environmental conditions has been repeatedly demonstrated. In this paper, the composition of FAs in the epiphytic ferns, Platycerium bifurcatum and Asplenium nidus, and the terrestrial fern, Asplenium trichomanes was analyzed by gas-liquid chromatography with mass spectrometry. The data obtained clearly indicate that epiphytic ferns have several distinctive features in the composition of their FAs. They are characterized by a high level of saturated FAs (about 50%) and a great variety of very-long-chain FAs (VLCFA). This strongly contrasts with the FAs composition in the terrestrial fern in which unsaturated FAs prevail. High levels of saturated fatty acids, in particular palmitic acid (16:0), together with a high VLCFA content, can be a necessary component in complex interactions with microorganisms. Thus, the specific FA composition of P. bifurcatum and A. nidus may act both as a protective mechanism against the penetration of bacteria and pathogenic fungi, and as a mechanism for the interaction of the epiphytes with saprophytic fungi. It is likely that the composition of FAs in the epiphytic ferns is determined by their habitat and plays an active role in the interaction of plants with their environment.

The population genetics of ferns, which results from initiation of individuals in a new location (often via long-distance dispersal) plus a wide range of mating systems, merit continued study. In the case of species in the subfamily Botrychioideae (specifically the genera Botrychium and Botrypus), previous work using allozyme and isozyme techniques revealed low genetic diversity and weak population genetic structure. This lack of genetic differentiation between populations is in spite of underground fertilization in the genus resulting in high levels of inbreeding and primarily fixed heterozygosity in tetraploids. In the present study, Amplified Fragment-Length Polymorphisms (AFLPs) were used to examine population genetics and structure of three species in the genus Botrychium and one species in the genus Botrypus. Measures of population genetic diversity were generally low, with the highest measures in the relatively common Botrypus virginianus. Across all species, measures of population differentiation were low and most genetic variation was contained within populations. Bayesian analysis of population structure using the program STRUCTURE corroborated these findings, with inferred genetic clusters that generally did not correspond to geographic collecting locations. These results agree with previous studies, with low genetic diversity within and among populations likely due to self-fertilization that limits outcrossing and long-distance spore dispersal that results in genetically similar populations.