We investigated the influence of microsite and establishment factors on the distribution of Botrychium pumicola Coville ex Underw. (Ophioglossaceae), an obligate mycorrhizal fern restricted to specialized volcanic habitats, predominately pumice, in the Cascade Range of central and southern Oregon and northern California. The fragmented distribution of this threatened species and its absence from suitable habitat is of conservation concern. At eight subalpine and one alpine site, plots with and without B. pumicola were compared for biotic and abiotic variables. Botrychium pumicola populations occurred with diverse perennial plants. Nearest neighbor analysis showed a clumped dispersion of B. pumicola with associated plants. Botrychium pumicola spores were found in soils of seven plots with and two without B. pumicola. In plots with B. pumicola, soil potassium was higher while soil density and soil temperatures were lower than in plots without B. pumicola. Airborne spores, collected in spore traps, were dispersed up to 10 m from source plants. Microsite factors (soil nutrients, soil density, nearest neighbor dispersion) and dispersal limitations are likely key factors influencing the distribution of Botrychium pumicola. Narrow spore germination requirements combined with dispersal limitations may influence population expansion of obligate mycorrhizal ferns such as B. pumicola.

A phylogenetic analysis of plastid rbcL sequences indicates that Pellaea flavescens from Brazil is nested within the Old World species Pellaea viridis. The morphology of these two species is similar and P. flavescens is here considered to be a synonym of the older P. viridis. This fern may have been introduced to and subsequently naturalized in Brazil or, alternatively, the natural result of long distance dispersal.

The monilophytes Blechnum spicant (L.) Sm. and Dryopteris affinis ssp. affinis (Lowe) Fraser-Jenkins show different reproductive strategies under in vitro conditions. While B. spicant exhibits asexual and sexual reproduction, with an antheridiogen system promoting outcrossing, D. affinis ssp. affinis reproduces only asexually through apogamy. Individuals of several populations of these species, collected in Principado de Asturias (Spain), were analyzed to test the influence of their mating system in the genetic variability displayed by each species. This study shows that the genetic diversity assessed in populations of each species collected in situ is in concordance with that expected according to their reproductive system previously observed in vitro. The genetic diversity found in D. affinis ssp. affinis was low and most of genetic variation can be attributed to differences among localities. This result indicates high fixation of the detected alleles within each locality, as expected for a clonal reproductive system. In the sexual species B. spicant the genetic diversity was higher. Our results confirm the importance of reproduction system in the genetic diversity present in populations of these fern species making essential to consider the definition and study of reproductive system and the associated consequences in the design of successful conservation actions.

Fern identification usually requires the use of mature sporophytes, since attempts to identify juveniles using morphological traits often provides unsatisfactory results. Here we examined young sporophytes found among boulders in a river basin of a xeric valley in central Peru. Attempts to identify these sporophytes first pointed to four different genera, two in Pteridaceae (Anogramma and Pityrogramma), and the others in Aspleniaceae (Asplenium) and Cystopteridaceae (Cystopteris). Here, we resolved this puzzle combining morphology and sequences of DNA (rbcL and trnG-R) that point to Pityrogramma trifoliata of Pteridaceae.