Matteuccia struthiopteris (Onocleaceae) has a present-day distribution across much of the north-temperate and boreal regions of the world. Much of its current North American and European distribution was covered in ice or uninhabitable tundra during the Pleistocene. Here we use DNA sequences and AFLP data to investigate the genetic variation of the fiddlehead fern at two geographic scales to infer the historical biogeography of the species. Matteuccia struthiopteris segregates globally into minimally divergent (0.3%) Eurasian and American lineages. These two clades have little to no variation even at large geographic scales. Within hemisphere, patterned genetic variation was evident only in the AFLP data and only locally. Genetic variation within Vermont was greater within the westward-trending Winooski River watershed than in the Passumpsic River watershed, which drains east into the Connecticut River. We suggest that historical factors have created this pattern; a Mississippi Valley Pleistocene refugium for the American lineage of the species seems plausible.

The cytological features of the cells taking part in archegonial development and oogenesis in the fern Plagiogyria euphlebia (Kunze) Mett. were described in detail by means of light and electronic microscopy. The archegonium develops from an initial cell, which contains dense cytoplasm in contrast to the somatic cells. Two divisions of the initial cell result in a tier of three cells. The middle of which finally develops into a neck canal cell, a ventral canal cell and an egg by two unequal divisions. During maturation, the egg cell becomes progressively isolated from the adjacent cells by forming a separation cavity, a casual wall and an egg envelope. Series sections show that a fertilization pore forms in the upper egg envelope. During maturation of the egg, the nucleus produces conspicuous evaginations. The phylogenetic relationship of the fern P. euphlebia is discussed according to the cytological features in oogenesis. The cytological features observed during oogenesis support the inclusion of Plagiogyriaceae among the tree-ferns as proposed from molecular analyses.

The genus Platycerium consists of about 18 species, commonly found in tropical and subtropical forests. Among the different species, Platycerium coronarium, P. platylobium, P. ridleyi and P. wallichi are found in Peninsular Malaysia, and P. coronarium is considered the most attractive ornamentally. Platycerium coronarium is an epiphytic fern, bears a gigantic morphology and is native to tropical areas of South America, Africa, Southeast Asia, Australia and New Guinea. Platycerium coronarium nests on the upper branches of the tallest trees in the forest. Due to having a uniquely-shaped fronds, they are famous for ornamental purposes, where they can be found in gardens, especially in tropical regions. Detailed morphological studies of this species are lacking. In the present work, data are reported aiming at defining both the macro- and micro-morphological characteristics of intact and in vitro P. coronarium. Data from scanning electron microscopy (SEM) revealed similar ultrastructures of both types of leaves, i.e., the presence of multicellular trichomes on both the abaxial and adaxial surfaces. Sunken stomata were also detected on the abaxial surface of the leaves. In addition, tissue culture studies were done to obtain an efficient regeneration system as well as to serve as an approach for conservation. Successful regeneration of sporophytes from gametophyte explants were observed in MS medium supplemented with 1.0–1.5 mg/l GA₃ and 30 g/l sucrose, at pH 5.8 under 16 hours light and 8 hours dark.

A new species, Pityrogramma opalescens, is described; it is known only from Cerro del Torrá, an isolated mountain peak in the Cordillera Occidental of Colombia, which is a region of high diversity and endemism. It is most similar to Pityrogramma lehmannii, and the two species differ from all other Pityrogramma species by having creeping rhizomes, rhizome scales with turgid cells, an elongate, proximally 1-pinnate lamina, with sessile segments supplied by multiple veins that emerge from the rachis rather than from a single main vein, and farina on the abaxial side of the lamina that is borne at the apex of short hairs. It differs from P. lehmannii by more numerous segments that are narrower (3.5–4.0 mm wide vs. 10.0–17.0 mm wide), with more acutely rounded apices, and dull-yellow rather than white farina abaxially.

Two new species of Elaphoglossum (Dryopteridaceae) are described and illustrated: Elaphoglossum bradeanum Melo & Salino and Elaphoglossum commissurale Melo & Salino, both endemic to Minas Gerais state (Brazil).

Morphological, cytological and taxonomical analyses of Asplenium delitescens and A. laetum in Cuba resulted in the recognition of both species belonging to the genus Hymenasplenium Hayata. The combinations of the Neotropical species to this genus are presented. Some remarks on gametophyte morphology of H. delitescens are included.

The genus Bolbitis from Vietnam and Laos is revised; 14 species and two varieties are recognized. A new species, Bolbitis lanceolata S. K. Wu & J. Y. Xiang is described and illustrated. Bolbitis scandens W. M. Chu ex Ching et C. H. Wang and B. yunnanensis Ching ex Ching et C. H. Wang are two new records in both Vietnam and Laos. Bolbitis hekouensis Ching and B. latipinna Ching are treated as synonyms for the first time.

Morphological, cytological, and isozyme studies of three plants of Polystichum fibrillosopaleaceum var. marginale (Dryopteridaceae) from Gotenba, at the foot of Mt. Fuji, Shizuoka Prefecture, Japan, and comparative observations of their lamina, scales, sori, spores, and perispore ornamentation, revealed them to be intermediate between P. fibrillosopaleaceum and P. igaense. Cytologically, the meiotic chromosome number of n = c. 38II 6I (2x) and the malformed spores of the three plants are characteristic of hybrid sterility. The electrophoretic polymorphisms of four isozymes (Pgi, Pgm-1, Pgm-2, and Skdh) were examined in the three plants and in 22 individuals of the putative parental species, P. fibrillosopaleaceum (11) and P. igaense (11). The heterozygous genetic patterns (Pgi-ab, Pgm-1ab, Pgm-2ab, and Skdh-ab) fixed in the putative hybrids indicate that they have a combination of the Pgi-b, Pgm-1b, Pgm-2a, and Skdh-a alleles of P. igaense and Pgi-a, Pgm-1a, Pgm-2b, and Skdh-b alleles of P. fibrillosopaleaceum. The morphological, electrophoretic features and chromosome numbers confirm the three plants to be diploid hybrids of P. fibrillosopaleaceum and P. igaense. We therefore conclude that P. fibrillosopaleaceum var. marginale is in fact a diploid hybrid and thus should not be given the variety status.

Chromosome numbers and reproductive biologies of 12 fern species from eight genera in the Polypodiaceae, (Colysis, Lepidogrammitis, Lepisorus, Microsorium, Neolepisorus, Phymatopteris, Phymatosorus, and Pyrrosia) from the southern region of China (Yunnan, Guangxi and Hainan) were investigated. The base number is x = 36 in these genera of Polypodiaceae. The chromosome numbers for four species: 2n = 72 (2x) in Lepidogrammitis drymoglossoides, 2n = 72 (2x) in Neolepisorus ovatus, 2n = 72 (2x) in Phymatopteris rhynchophylla, and 2n = 72 (2x) in Phymatosorus hainanensis are here reported for the first time. Four records: 2n = 72 (2x) in Colysis hemionitidea, 2n = 72 (2x) in Lepisorus thunbergianus, 2n = 108 (3x) in Phymatopteris crenatopinnata, and 2n = 108 (3x) in Phymatosorus cuspidatus are new cytotypes. Lepisorus thunbergianus 2n = 72 (2x) has the base number of x = 36, diverging from those cited in previous reports (x = 25, 38, 50, and 51). The reproductive type in P. crenatopinnata and P. cuspidatus is apogamous, whereas in the other species it is of the sexual reproductive type.