A comprehensive revision of the genus Protousnea is presented based on morphological, chemical, anatomical, and extensive field studies in the Patagonian Andes and Tierra del Fuego, as well as by comparisons with herbarium material. A complete chemical profile is detailed for each species and sekikaic acid has been shown to be the major medullary metabolite. The new despide, 4′-O-demethylsubsekikaic acid, is described for the first time. The circumscription of species and intraspecific variability is discussed with reference to key morphological, anatomical, and chemical characters, as well as ecological preferences. Conidia are described for the first time. Protousnea malacea and P. scrobiculata have been synonymized with P. poeppigii. A key to the species is given. All the species are illustrated and new data are presented on their distribution, substrate preferences, and ecology.

A hornwort classification that recognizes 11 genera, comprising a hierarchy of two classes, three orders, and four families is proposed. The updated checklist of these bryophytes for North America has been expanded from 11 species in three genera to 17 species in five genera. Application of the genus name Anthoceros in the traditional sense is clarified.

Due to its high rate of homologous recombination, the moss Physcomitrella patens (Hedw.) B.S.G. is used as a novel system to facilitate gene/function-analyses. Loss-of-function mutations are easy to identify in the moss, as the dominant phase is the haploid gametophyte. Regenerating protoplasts were used to establish different moss lines with ploidy levels of 1C, 2C, and 4C. Flowcytometric analysis of three haploid, three diploid, and two tetraploid Physcomitrella lines revealed that haploid and diploid lines were cytologically stable, whereas nuclei of tetraploid lines exhibited varying DNA-contents. The effect of polyploidization on the phenotype, growth, and differentiation of Physcomitrella was investigated in vitro. The growth of three haploid, three diploid, and two tetraploid genotypes was evaluated after four weeks of axenic culture. The effect of the genotype on the growth rate of plants cultured on minimal medium was statistically significant; in contrast the ploidy level had no effect. On full medium the effect of the line, as well as the ploidy level, were statistically significant. The dry weight per petri-dish after a culture period of four weeks, was 103–106 mg in haploid lines, 64–78 mg in diploid, and 19–32 mg in tetraploid ones. The effect of the moss line and the ploidy level on differentiation of buds and gametophores was highly significant. Tetraploid moss rarely developed buds and/or gametophores. Sporophyte induction was observed in haploid and diploid genotypes, however not in tetraploid moss. Twelve percent of the germinated spores increased the ploidy level in comparison with the parent plant. A reduction of the ploidy level from 2C to 1C was observed in 7%. Evaluation of older plants (11 weeks after protoplast isolation) showed that polyploidization often resulted in a reduced number of gametophores and a reduced colony diameter on minimal medium compared to haploid plants. More than 70% of the diploid plants had gametophores with phenotypic alterations. Only 1.4% of the diploid plants were indistinguishable from wildtype. Changes in leaf shape and multiple phenotypic deviations from wildtype are most likely indications of polyploidization; however, the unequivocal identification of diploid plants is only possible using flowcytometric analysis, because a multitude of different phenotypic changes were observed in polyploid plants.

Lantzius-Beninga (1815–1871), influenced by the earlier work of Hedwig (1730– 1799), investigated the capsules of mosses, and more specifically characteristics of the peristome. He was the first to show that longitudinal sections of the capsule and peristome teeth at the capsule mouth provided characters useful to distinguish species. Limpricht (1888–1903) integrated the findings of Lantzius-Beninga into his species descriptions in Kryptogamen-Flora von Deutschland, Österreich und der Schweiz. The ideas of Lantzius-Beninga were later taken up by S. Edwards; J. Shaw and H. Robinson; and J. Shaw, L. Anderson and B. Mishler for taxonomic research, although the technique of sectioning the capsule and peristome has not been widely adopted by bryologists. Drawings of longitudinal sections through peristome teeth of selected species of Grimmia are presented here to illustrate specific differences between them using the technique of Lantzius-Beninga. We show that it is possible to correlate some variable characters of the gametophyte with the characters of the sporophyte, specifically longitudinal sections of the peristome and capsule at the capsule mouth, and to clearly separate taxa on the basis of peristome differences. A paragraph concerning sectioning methods is included.

New to the Americas is Anoectangium handelii Schiffn., which differs significantly from A. aestivum (Hedwig) Mitt. by its small size, axillary propagula, and cauline leaves usually blunt and shorter than the perichaetial leaves. Previously, this species was known only from south-central Eurasia.

The effects of fragmentation of the sub-humid low-boreal forest in agro environments on bryophyte and lichen diversity were analyzed on 44 woodlots in three regions of northern Alberta, Canada. Woodlots were selected to cover a wide variety of shapes and sizes in each area. Several microclimatic variables, which included temperature at three different heights above the forest floor, relative humidity, and the amount of light penetration were measured in five m diameter circular sample plots along transects that covered the length and the width of each fragment. The number of microhabitats that included living trees with creviced and smooth bark, standing dead, different decay classes of downed woody debris, soil and rock were tabulated at each sample plot. Bryophyte and lichen presence was noted for all microhabitats found within each plot. There was a trend of decreasing temperature and light intensity and increasing humidity up to 15 m from the edge of the fragments. A multiple regression analysis revealed that the distance from edge and the habitat heterogeneity were the most important variables affecting bryophyte and lichen species richness. Further analysis indicated that edge effects were significant for bryophytes, but not for lichens. The size and shape of fragments had a significant effect on habitat heterogeneity, and bryophyte and lichen diversity. Although there was a distinction between the floras in each region, the effects of fragment size and habitat heterogeneity were similar. An indicator species analysis selected several indicators of large, medium, and small fragments that were also indicators of habitat heterogeneity and species richness. The presence or absence of several indicator species is used to produce performance benchmarks for habitat heterogeneity and species richness. The use of indicator species offers an inexpensive and relatively easy method to evaluate edge effects and habitat heterogeneity on bryophyte and lichen diversity in woodlots.

The role of substrate diversity in forest ecosystems in maintaining bryophyte diversity is frequently acknowledged in the bryological literature, but there are few large-scale studies that attempt to disentangle the effect of substrate type and temporal features. We investigated the interaction between substrate type and forest age, which is a contentious issue in landscapes managed for wood production. We studied three age classes, 1–18 years, 33–67 years, and ‘old growth’ forest aged more than 110 years. We investigated the species distribution of bryophytes growing on 15 vascular species, logs, fallen branches, soil, rocks, upturned root bases, stumps, roots, and dead trees. A total of 49 substrate type-age class groups were sampled. Many bryophyte species were found only to occur on one substrate type, but these substrate types were found in more than one forest age class. A number of bryophyte species were restricted to a group of like substrate types, for example Neckera pennata, Calyptopogon mnioides, and Daltonia splachnoides were found only on ‘vertical’ substrate types–Acacia dealbata, Pomaderris apetala, and fallen branches in 33–67 year old forest. There was evidence for a number of bryophyte species preferring logs in forest aged 33–67 years with most of these species also preferring old growth logs. Eucalyptus obliqua trees of 33–67 year old forest and old growth forest supported many of the same preferential bryophyte species, unlike E. regnans trees. A number of these same eucalypt-dwelling bryophyte species were positively associated with fallen branches, logs, and soil in both forest aged 33–67 years and old growth forest. Under current forest management, there is no specific prescription for retention of any substrate type. Coupled with the current 80–100 year harvest rotation time, the bryophyte species may be at risk of exclusion from wood production areas.

This study examined bryophyte community composition in relation to microsite and microenvironmental variation at different scales in three conifer-dominated stands in the boreal forest of Alberta, Canada. We documented bryophyte assemblage on specific microsite types (physiognomic forms providing substrates for moss colonization: logs, stumps, tree bases, undisturbed patches of forest floor, disturbed patches of forest floor), and at coarser scales: mesosites (625 m² plots within stands), and stands (10 ha). Patterns of variation in bryophyte composition arising from the microsite sampling were clearly related to microsite type and, for woody substrates, to microsite quality (decay class; hardwood vs. softwood). Microenvironment (moisture, pH, temperature, light) also had some influence on bryophyte composition of woody microsite types. Forest floor moisture, pH, and light were related to bryophyte composition of undisturbed patches of forest floor while forest floor moisture and temperature were significant correlates for disturbed forest floor. At the coarser-scale, surface moisture and forest floor moisture were related to bryophyte assemblage of mesosites; this was partially reflective of differences among stands. We conclude that bryophyte species composition in these forests is related to a hierarchy of factors including fine scale variation in the type and quality of available microsites along with microenvironmental variation at different scales. Management efforts to preserve bryophyte biodiversity will need to incorporate this complexity.

The role of dew, fog, and rain in the development of reproductive organs in the moss Bryum dunense A.J.E. Smith & H. Whitehouse (B. bicolor complex) was examined in three different microhabitats within a dune field in the Negev Desert. Growth and reproduction were compared prior to the first rainfall of the winter and subsequently twice during the winter. The microhabitats, differing in their exposure to radiation and precipitation, were 1) an exposed site, 2) a shaded (under a shrub canopy) site, and 3) a partially shaded microhabitat at the foot of a north-facing dune slope. We hypothesized that both microhabitat and time of year would impact the reproductive strategies of the species. In all three microhabitats, reproductive organs were initiated prior to the first winter rain. The source of bryophyte wetness was atmospheric humidity from dew and fog. The type and the extent of development of the reproductive organs was habitat dependent. Prior to the rains, antheridia and archegonia were scarce in the exposed microhabitat, in small numbers in the shaded microhabitat, and most abundant in the partially shaded microhabitat. Subsequently, sporophytes were formed more often in the partially shaded microhabitat following the winter rains. Asexual propagation by bulbils was prevalent at the partially shaded and the exposed microhabitats, whereas regeneration by secondary protonemata was especially abundant at the shaded microhabitat. Bryum dunense is highly adapted to dew and fog utilization and is able to develop reproductive organs prior to the first rains. In this way, plants are prepared for dispersal by bulbils and ready for fertilization with the onset of the first rain. This early initiation of reproductive development is especially advantageous for dioicous species in unpredictable desert environments enabling the completion of the life cycle. The partially shaded microhabitat formed by the shrub canopy was found to be the most suitable microhabitat, yielding the highest amounts of sexual (antheridia and archegonia) and asexual (bulbils) organs. The shrub may thus serve as an ‘island of fertility’ for B. dunense.

Protein Kinase C-like activity was established in Marchantia polymorpha. Different concentrations were detected in young and old tissue extracts from untreated and spermine-treated thalli after agarose gel electrophoresis in the presence of a PKC-specific fluorescent tags. Cytosolic putative PKC concentrations (nmol/g tissue) in untreated young thalli were higher than concentrations in old tissue. Old spermine-treated tissue possessed higher cytosolic putative PKC concentrations than young untreated thalli. Both young and old spermine-treated tissue extracts possessed higher total protein levels than young and old untreated tissue extracts. The data suggest that spermine-treatment evoked a qualitative and quantitative decrease in senescence.

Polysaccharides of foliose thalli of Pseudocyphellaria clathrata (De Not.) Malme, a fungus lichenized with a green photobiont, were extracted and chemically characterized. The thalli were successively extracted with water and 2% aqueous KOH, at 100°C. After neutralization, the solution was subjected to freeze-thawing and Fehling treatment of the supernatant precipitated a structurally complex galactoglucomannan (GGM) that was identical to a similar fraction obtained from Pseudocyphellaria aurata (Ach.) Vainio, a fungus lichenized by the green alga Dictyochloropsis symbiotica. Isolated from the supernatant of the Fehling precipitation, was an arabinogalactomannoglucan (AGMG) that contained arabinose, galactose, mannose, and glucose in a 12:34:40:14 molar ratio. Methylation analysis showed 18 different structures, the principal being nonreducing galactofuranosyl end-units (25%) with the main chain composed by (1→3)-linked β-glucopyranosyl units, as seen by controlled Smith degradation.

The taxonomic and nomenclatural implications of phylogenetic studies of the Bryaceae are presented. Bryum algovicum Müll. Hal., B. archangelicum Müll. Hal., B. capillare Hedw., B. bimum (Schreb.) Turner, B. cyclophyllum (Schwägr.) Bruch & Schimp., B. donianum Grev., B. lisae De Not., B. meesioides Kindb., B. orthothecium Card. & Broth., B. pallens Sw., B. pallescens Schwägr., B. purpurascens (R. Br.) Bruch & Schimp., B. uliginosum (Brid.) Bruch & Schimp., and B. wrightii Sull. are transferred to Plagiobryum Lindb. Brachymenium acuminatum Harv., B. philonotula Broth., and B. preissianum Hampe (A. Jaeger) are transferred to Bryum Hedw. Finally, the genus Imbribryum is described comprising B. alpinum With, B. blandum Hook. f. & Wilson, and Bryum muehlenbeckii Bruch & Schimp.

The rare, North American, high plains moss, Molendoa ogalalensis (G. L. Smith) R. H. Zander, is newly recorded for stations in Sonora, Mexico.

Lepraria toensbergiana Bayerová & Kukwa, a new lichen species from Europe is described. It is similar in morphology and ITS sequence to the widespread L. jackii Tønsberg, but different in chemistry. It contains atranorin and toensbergianic acid as major secondary metabolites. The distribution of the taxon is rather well defined, being found especially in mountain areas. A key to Lepraria species in Europe containing only fatty acids and atranorin is provided.

A hornwort is reported from Dominican amber (Eocene–Oligocene). The specimen shows the horn-like sporophytes typical for this group of plants and can be placed into the Dendrocerotaceae, although an exact placement in Dendroceros or Megaceros cannot be made, it is the first record of a fossil hornwort.