Scanning electron microscope (SEM) studies of xylem of three species of Equisetum reveal numerous details not previously reported on the basis of light microscopy. SEM images of thick (ca. 1 mm) sections reveal pit shapes, cell contexts, and microstructure of pit membranes. Pit shapes are remarkably diverse in comparison to those of ferns or conifers. Nodal tracheary elements are isodiametric to fusiform in shape, and have crowded circular (mostly) to elongate prominently bordered pits and uniformly thick secondary walls. Internodal tracheary elements, by contrast, have relatively large circular pits with inconspicuous borders. Secondary walls of internodal tracheids are thin, with thickenings that are annular, looplike, or of some intermediate form. Metaxylem internodal tracheary elements line the inner surface of carinal canals ( =  proxylem lacunae), and many of the large circular (often crateriform) pits facing the canals may lack pit membranes, especially in E. giganteum and E. myriochaetum. Because dye experiments show that carinal canals can conduct water in stems of Equisetum, the fact that portions of tracheary elements facing the canals may have perforations (many of the pits in E. myriochaetum lack pit membranes despite careful handling techniques) is significant. This opens the possibility that internodal tracheary elements may, in some species, be vessel elements that permit conduction from the carinal canals of one internode to those of the next internode (carinal canals are not intercontinuous between internodes), aided by metaxylem tracheids of the nodal plates. Such vessel elements would not be the same as those reported by Bierhorst, who found vessels only a few vessel elements long in rhizomes.

Nucleotide sequences from four plastid genes (rbcL, atpB, atpA, rps4) were used to infer relationships of Diplaziopsis and Rhachidosorus. The phylogenetic positions of these two Asian fern genera have been debated, and neither had been included in the most recent global molecular systematic studies of ferns. Our four plastid gene sequence analyses supported a sister relationship between Diplaziopsis, Rhachidosorus and the North American Homalosorus, the monophyletic group of the newly-examined genera is an early diverging lineage of Woodsiaceae, and far away from athyrioid ferns. The inferred relationships of Diplaziopsis and Rhachidosorus are not consistent with most recent treatments, while, some synapomorphic characteristics are shared with these two genera. Further studies on more morphological characters and gametophytes of these two genera are needed to test these relationship hypotheses.

The section Thamnopteris is morphologically distinct among the large fern genus Asplenium, but the species recognition within this section is very difficult. To understand the species concept of this section from a cytological view, I examined chromosome numbers of fifteen samples representing eight taxa (species and intraspecific taxa). As result, seven taxa were determined to be sexual tetraploids with chromosome number 2n  =  144 and Asplenium humbertii is a sexual hexaploid with 2n  =  216. Along with the chromosome numbers reported, notes on nomenclature, diagnostic characters, and geographical distribution for the eight taxa are given. Cytological data available so far indicate that Asplenium sect. Thamnopteris is not a monophyletic group.

Plants have different strategies for adapting to environmental conditions, such as characteristics that allow them to be more efficient in shady or sunny environments. Those that grow in dimly lit environments often have a photosynthetic epidermis. However, Adiantum raddianum, known as the maidenhair fern, is a species found in sunny environments that has this characteristic. Within the abaxial and adaxial epidermal cells of the leaf pinnules of this species, there are arm-like projections where chloroplasts agglomerate. The goal of this study was to describe the development of the epidermal cells of A. raddianum, describe the morphological characteristics of the chloroplasts in these cells, and interpret any cytological characteristics that this species might have as a result of an adaptive survival strategy. The study found that the arm-like projections within the epidermis develop when the leaves are young and still exhibit circinate vernation. Cytological observations revealed a plastidial dimorphism, where there was variation in the arrangement of the thylakoid system, and the presence of stromules, which may help establish a connection among chloroplasts and between these organelles and mitochondria and peroxisomes. Descriptions of the stromules and plastidial dimorphism, made in this study, can be included with other known epidermal adaptive strategies (e.g., plastidial movement and mucilage secretion), which help this plant to survive under different environmental conditions.

In the present study, we investigated a natural population of H. serrata in the Bawangling Nature Reserve of Hainan Province, South China. In field sampling, we examined the number of adult plants, gemmlings and sporelings as well as the gemma number of plants at different ages. A significant difference was observed between the numbers of gemmlings and sporelings. Most seedlings derived from gemmae, which critically influenced the population regeneration. The reproductive ability of gemmae became stronger from the 4th year of gemma growth. In the cultivation test, gemmae were planted in three different soil media, i.e., habitat soil, sand and humus. No significant difference was found in the gemmation rate among the three media, but the survival rate in sand was significantly lower than in the other two media. We also investigated the morphology of the gemma and gemmling growth pattern of H. serrata. The results may reveal the contributing role of gemmae in reproductive strategies, and be helpful to the resource protection and cultivation of H. serrata.

An ethnobotanical study was performed of the ferns and lycophytes used by the Guaraní of Misiones Province, Argentina. It was determined that fifty species are used, and details of the uses and the Guaraní names and nomenclature are given and discussed. Fern and lycophytes are used for medicines, crafts, in magic rituals, and marketing of the plants. The most important traditional use of ferns is for medicine and the most important modern use is commercialization for use in horticulture.