Polystichum has often been treated as a sub-cosmopolitan genus of 180-230 species (i.e., Polystichum s.l.), but several segregate genera, such as Cyrtogonellum, Cyrtomidictyum, Cyrtomium, Phanerophlebia, and Sorolepidium, have been recognized in various treatments. Together, these genera constitute the polystichoid ferns. We used a data set of 47 species of the polystichoid ferns and three outg...

In today's angiosperm-dominated terrestrial ecosystems, leptosporangiate ferns are truly exceptional--accounting for 80% of the approximately 11,000 nonflowering vascular plant species. Recent studies have shown that this remarkable diversity is mostly the result of a major leptosporangiate radiation beginning in the Cretaceous, following the rise of angiosperms. This pattern is suggestive of a...

Barnsley (2006) used chaos game in function systems and it gave rise to interesting fractals by combining it with function iterations. A fractal fern is generated by taking different probabilities in the chaos game. In this paper, we introduce two advanced iterations from nonlinear analysis into the study of IFS for generation and pattern recognition of new fractal ferns. Gottfried (1991), and ...

BACKGROUND Molecular phylogenetic investigations have revolutionized our understanding of the evolutionary history of ferns-the second-most species-rich major group of vascular plants, and the sister clade to seed plants. The general absence of genomic resources available for this important group of plants, however, has resulted in the strong dependence of these studies on plastid data; nuclear...

The plastid genome (plastome) is a rich source of phylogenetic and other comparative data in plants. Most land plants possess a plastome of similar structure. However, in a major group of plants, the ferns, a unique plastome structure has evolved. The gene order in ferns has been explained by a series of genomic inversions relative to the plastome organization of seed plants. Here, we examine f...

Ferns are one of the few remaining major clades of land plants for which a complete genome sequence is lacking. Knowledge of genome space in ferns will enable broad-scale comparative analyses of land plant genes and genomes, provide insights into genome evolution across green plants, and shed light on genetic and genomic features that characterize ferns, such as their high chromosome numbers an...

Pharmacological activity (e.g. antipsychotic ac­ tion [1]) and chemotaxonomic interest of xanthones may explain the increasing interest in these substances in recent years. It has been suggested [2] that Cystopteris fragilis complex is the most inter­ esting biosystematic problem in ferns. Xanthone analysis may be of interest in the study of relation­ ships of the taxa of this complex since pre...

The eupolypods II ferns represent a classic case of evolutionary radiation and, simultaneously, exhibit high substitution rate heterogeneity. These factors have been proposed to contribute to the contentious resolutions among clades within this fern group in multilocus phylogenetic studies. We investigated the deep phylogenetic relationships of eupolypod II ferns by sampling all major families ...

Herbaceous plants rely on a combination of turgor, ground tissues and geometry for mechanical support of leaves and stems. Unlike most angiosperms however, ferns employ a sub-dermal layer of fibers, known as a hypodermal sterome, for support of their leaves. The sterome is nearly ubiquitous in ferns, but nothing is known about its role in leaf biomechanics. The goal of this research was to char...

Heterosporous water ferns (Marsileaceae and Salviniaceae) are the only extant group of plants to have evolved heterospory since the Paleozoic. These ferns possess unusual reproductive structures traditionally termed ‘‘sporocarps.’’ Using an evolutionary framework, we critically examine the complex homology issues pertaining to these structures. Comparative morphological study reveals that all h...