We conducted desiccation and rehydration experiments on the detached leaves of 43 pteridophyte species to assess the variability of drought adaptation strategies among pteridophytes. We found complete grades of desiccation responses from poikilohydric to homoiohydric strategies and within the latter category from mesomorphism to xeromorphism. These results suggest that pteridophytes have repeatedly evolved a wide variety of drought adaptation strategies (poikilohydry and xeromorphism at least 12 and 6 times, respectively) that are not adequately described by a simple distinction between homoiohydry and poikilohydry.

This study investigated the current distribution of an invasive tropical fern, Thelypteris dentata, and its habitat type in three Japanese prefectures (Osaka, Kyoto, and Shiga) in the Kinki District. The results showed that T. dentata has expanded its distribution into highly urbanized areas in Osaka Prefecture and has reached southern Kyoto Prefecture and central Shiga Prefecture. The distribution of T. dentata populations thus seems to have expanded northward based on comparisons with the distribution that was determined in the 1980s. Because the fern's habitat types were mainly the side walls or bottoms of drainage channels, crevices in stone walls and roadsides, the urban matrix has not served as a barrier to the expansion of the range of T. dentata; on the contrary, it may be serving as a type of heat island corridor that is facilitating the spread of this species.

Longisections of xylem were studied with scanning electron microscopy (SEM) for roots of Angiopteris, upright axes of Psilotum, and rhizomes of eight species of leptosporangiate ferns of diverse habits and varied ecological preferences. In contrast to earlier studies using macerations, razor-blade sections of fixed material from living plants were prepared. All materials studied showed porose or reticulate pit membranes present on presumptive end walls of tracheids. Contrasting non-porose pits were observed on lateral walls of some tracheids. Tracheid to parenchyma pit pairs may have porose pit membranes on the tracheid side and nonporose pit membranes on the parenchyma side; thus degree of porosity in a section can represent the degree to which one primary wall or the other is pared away. Reticulate pit membranes on tracheary element end walls are evidently widespread in ferns. Such cells should not be considered vessel elements, although the reticulate pit membranes suggest a degree of transition toward the membrane-free perforations of typical vessels. True vessels (pit membranes absent in perforations) do occur in roots in a limited number of fern genera. The preparation methods of the present study produced results freer from artifacts than did macerations, and interpretations must be altered accordingly. Reports of lateral, multiple, and interrupted perforation plates in ferns are probably the result of loss of pit membranes due to the oxidative action of maceration and should be rejected. Likewise, “pit dimorphism” (alternately wide and narrow pits) and “striate” (corrugated) pit membranes in ferns represent artifacts. True vessel elements in ferns probably always have secondary wall architecture of end walls different from that of lateral walls.

A new species of Doryopteris is here described, illustrated and its diagnostic characters discussed. Material of the new taxon, Doryopteris majestosa, has been misinterpreted as Doryopteris nobilis as it has features similar to it, such as the lamina architecture and large fronds, but differs mainly in having proliferous buds at the base of the lamina amongst other characters.

Isoetes araucaniana is newly described from central Chile. This aquatic species is endemic to Araucanía and is the only southern Andean species with strongly and densely reticulate megaspores.

A new deer fern hybrid, B. corralense × B. mochaenum subsp. mochaenum, is described on the basis of macro- and micromorphological characters. Previous reports of this hybrid combination are excluded. In addition, new data on the distribution of B. corralense are reported, including its presence in Argentina.